Air filter systems, filter bag assemblies, filter bags and methods

ABSTRACT

Air filter systems, filter bag assemblies, filter bags and corresponding methods are described herein. Air filter systems, filter bag assemblies, filter bags and corresponding methods are described herein. The filter bag assemblies include a flange assembly, a cage attached to the flange assembly, and a filter bag installed over the cage with an opening at the flange assembly. When installed in the dirty air chamber of the air filter system, a seal between the flange assembly and the tubesheet defining the dirty air chamber is provided by applying a seal force on the end of the filter bag assembly located proximate the access panel on the side of the dirty air chamber opposite the tubesheet. That seal force is transmitted to the flange assembly through the cage. The tubular filter bags may be in the form of triangular bags and/or may include bag support connectors at the closed end of the bag.

RELATED APPLICATION

The present application claims the benefit of U.S. ProvisionalApplication Ser. No. 62/899,938 filed 13 Sep. 2019, entitled AIR FILTERSYSTEMS, FILTER BAG ASSEMBLIES, FILTER BAGS AND METHODS which isincorporated by reference in its entirety.

Air filter systems, filter bag assemblies, and filter bags along withcorresponding methods are described herein.

Many industries encounter particulate matter suspended in theatmosphere. In some industries, this particulate matter is a valuableproduct (for example, starch), and it would be beneficial if thesuspended particulate matter could be recovered and reintroduced intothe process. For other industries (for example, metal or wood working),it may be desirable to remove the particulate matter from the air inorder to provide a clear working environment.

Some systems for cleaning an air or other gas streams laden withparticulate matter include filter bags (sometimes referred to as socks)located in a housing. The filter bags are typically constructed offilter media, e.g., fabric, pleated paper, etc. The gas streamcontaminated with particulate matter is typically passed through thehousing so that the particulate matter is captured and retained by oneor more filter bags.

Air filter systems typically include a clean air chamber and a dirty airchamber. The two chambers are separated by a structure that is commonlyreferred to as a tubesheet. The tubesheet has a number of openings sothat air can pass between the clean and dirty air chambers. The filterbags are positioned over the openings so that particulate-laden air(dirty air) introduced into the dirty air chamber must pass through afilter bag to move into the clean air chamber. The particulate matter inthe dirty air collects on the filter bags as the air moves through thefilter bags.

From the clean air chamber, the cleaned air is exhausted into theenvironment, or recirculated for other uses. See, for example, U.S. Pat.No. 3,942,962 (Duyckinck), U.S. Pat. No. 4,218,227 (Frey), U.S. Pat. No.4,424,070 (Robinson), U.S. Pat. No. 4,436,536 (Robinson), U.S. Pat. No.4,443,237 (Ulvestad), U.S. Pat. No. 4,445,915 (Robinson), U.S. Pat. No.4,661,131 (Howeth), U.S. Pat. No. 5,207,812 (Tronto et al.), U.S. Pat.No. 4,954,255 (Muller et al.), U.S. Pat. No. 5,222,488 (Forsgren), U.S.Pat. No. 5,211,846 (Kott et al.), U.S. Pat. No. 5,730,766 (Clements),U.S. Pat. No. 6,090,173 (Johnson et al.), U.S. Pat. No. 6,902,592 (Greenet al.), and U.S. Pat. No. 7,641,708 (Kosmider et al.).

As the filter bags capture particulate matter, flow through the systemis inhibited and periodic cleaning of the filter bags can be performedto increase air flow through the system. Cleaning can be accomplished byperiodically pulsing a brief jet of pressurized air into the interior ofthe filter bag to reverse the air flow through the filter bag, causingthe collected particulate matter to be driven off of the filter bag. Thepressurized air may be directed into pulse collectors as described in,e.g., U.S. Pat. No. 3,942,962 (Duyckinck), U.S. Pat. No. 4,218,227(Frey), U.S. Pat. No. 6,090,173 (Johnson et al.), U.S. Pat. Nos.4,395,269, 6,902,592 (Green et al.), U.S. Pat. No. 7,641,708 (Kosmideret al.), and US Patent Application Publication US 2006/0112667 A1.

SUMMARY

Air filter systems, filter bag assemblies, filter bags and correspondingmethods are described herein.

In one or more embodiments, the filter bag assemblies include a flangeassembly, a cage attached to the flange assembly, and a filter baginstalled over the cage with an opening at the flange assembly. Wheninstalled in the dirty air chamber of the air filter system, a sealbetween the flange assembly and the tubesheet defining the dirty airchamber is provided by applying a seal force on the end of the filterbag assembly located proximate the access panel on the side of the dirtyair chamber opposite the tubesheet. That seal force is transmitted tothe flange assembly through the cage.

Providing the seal force at the end of the filter bag assembly andtransmitting that force through the cage to the flange assembly allowsfor removal and replacement of the filter bags (and the filter bagassemblies) through access ports on an access panel located across thedirty air chamber. As a result, the used filter bags (and theparticulate matter collected on them) do not pass through, andpotentially contaminate, the clean air chamber of the air filter system.

Another potential advantage of providing and transmitting a seal forceat the end of the filter bag assembly and transmitting that forcethrough the cage to the flange assembly is that other components suchas, e.g., pulse generators, etc. need not be removed or even partiallydisassembled to accommodate removal and replacement of filter bags.

Forming a seal using a filter bag by transmitting a seal force through acage located in the interior of the filter bag may also improve pulsecleaning of at least some types of particulate matter because the rapidacceleration associated with pulse cleaning of some filter bags(sometimes referred to as “bag snap”) can be retained (as compared to,e.g., the pulse cleaning of rigid filter cartridges).

In one or more embodiments, the filter bag assemblies described hereinmay include the triangular filter bags may be described as having theshape of triangular columns, with a height or length of the column beingarranged generally horizontally within the dirty air chamber and abottom surface of the triangular filter bags facing downward. In one ormore embodiments, the bottom surfaces of the filter bags are rapidlyaccelerated downward during pulse cleaning. As a result, particulatematter dislodged from the bottom surfaces of the filter bags duringpulse cleaning is advantageously driven directly into a hopper of thefilter system under the force of the filter media movement in additionto the force of gravity.

In one or more embodiments, pulse cleaning of the triangular-shapedfilter bags also results in rapid outward acceleration of the sidesurfaces of the triangular-shaped filter bags similar to that found inconventional envelope shaped filter bags. That rapid outwardacceleration may result in dislodgment of particulate matter collectedon those side surfaces similar to dislodgment in conventional envelopeshaped filter bags, with the dislodged particulate matter also fallinginto a hopper of the filter system under the force of gravity. Thecombination of bottom facing surfaces and side surfaces found in thetriangular-shaped filter bags described herein results in a synergisticeffect in which particulate loading and pulse cleaning are both improvedover conventionally shaped filter bags.

In one or more embodiments in which the generally horizontally-arrangedtriangular filter bags have the shape of triangular columns withdownward facing bottom surfaces, the width of the bottom surfaces may besmaller than the height of the side surfaces measured from the topvertex of the triangular shaped filter bag (where the width of thebottom surface is measured between the vertices defining the bottomsurface in a plane that is generally transverse to the columnheight/length and the height of the side surfaces being measured betweenthe top vertex and the bottom vertex defining the side surface). In oneor more embodiments, the width of the bottom surface may be 50% or less,40% or less, 30% or less, 20% or less, 15% or less, 12% or less, 10% orless, 8% or less, or 5% or less of the height of either side surface ofthe pair of side surfaces. At a lower end, the width of the bottomsurface may be 4% or more, 5% or more, 6% or more, 8% or more, 10% ormore, 12% or more, 15% or more of the height of either side surface ofthe pair of side surfaces.

In one or more embodiments in which the generally horizontally-arrangedtriangular filter bags have the shape of triangular columns withdownward facing bottom surfaces, triangular-shaped bags and/or the cagesused to support them may be described with respect to the included angleformed between the side surfaces at the tops of the triangles. In one ormore embodiments, the angle formed between the side surfaces at thevertex/apex/top of the triangular shaped bags and/or cages may be 45° orless, 30° or less, 20° or less, 15° or less, 12° or less, 10° or less,or 5° or less. At the lower end. the included angle may, in one or moreembodiments, be 2° or more, 3° or more, 4° or more, or 5° or more.

In one or more embodiments of triangular filter bags including atriangular end cap attached to a tubular body, the triangular end cap,when projected onto a flat surface along a bag axis extending from thebag opening to the triangular end cap, defines a height between the apexand the bottom edge and also defines a width across the bottom edgebetween the side edges. In one or more embodiments, the height may be 4or more, 6 or more, 8 or more, 10 or more, 12 or more, or 15 or moretimes the width, and, at an upper end, the height may optionally be 20or less, 15 or less, 12 or less, 10 or less, 8 or less, or 6 or lesstimes the width.

In one or more embodiments, air filter systems using generallyhorizontally-arranged filter bags shaped or formed into triangularcross-sections as described herein may exhibit improved particulateloading capacity because the filter media forming the bottom surfaces orbases of the triangles face downward. The downward facing filter mediamay, in or more embodiments, be less susceptible to particulate loadingduring use than filter media facing upward (in addition to enhancingpulse cleaning by releasing dislodged particulate matter downward whereit may, for example, land directly in a hopper located below the filterbags).

Further, by limiting the width of the bottom surfaces of thetriangular-shaped filter bags, the side surfaces of thetriangular-shaped filter bag assemblies form relatively steep verticalangles having generally vertical side surfaces. Those generally verticalside surfaces may serve to limit particulate loading on the sidesurfaces (as compared to, e.g., side surfaces arranged at shallowerangles). The generally vertical side surfaces that are the result of therelatively steep vertical angles also promote release of particulatematter collected on those side surfaces during the pulse cleaningprocess.

In one or more embodiments of the air filter systems described hereinincluding triangular filter bags, the filter bags are supported in adirty air chamber such that the filter bags and their supportingassemblies (e.g., flange assemblies, cages, etc.) can be removed andreplaced without passing through the clean air chamber of the air filtersystem. That limits or prevents contamination of the clean air chamberby particulate matter dislodged during removal of used filter bags thatis associated with removal of used filter bags through the clean airchamber.

Air filter systems that include one or more of the various features andcomponents described herein may offer one or more advantages such as,e.g., improved energy efficiency, reduced noise generation, etc. by, inone or more embodiments, reduced pressure drops within the air filtersystems both during primary flow operation and pulse cleaning of thefilter elements (where primary flow operation occurs when the air filtersystem is removing particulate matter from a dirty air stream), reducingfrictional losses in the air filter systems (both during primary flowoperation and pulse cleaning of the filter bags, improving particulateloading characteristics (thus potentially requiring fewer cleaningpulses), etc.

The air filter systems, filter bag assemblies and filter bags describedherein are designed for use in industrial air filter applications inwhich particulate matter must be removed from relatively large volumesof dirty air. As such, the filter bags and filter bag assemblies must besized to handle those air volumes and the particulate matter associatedwith the volumes. Generally, the filter bags described herein may have abag length measured from the bag opening to the closed end of the bagthat is 0.3 meters or more, 0.5 meters or more, or even 1 meter or more.The associated bag height (measured transverse to the length of the bag)may be 0.2 meters or more, 0.3. meters or more, 0.4 meters or more, or0.5 meters or more.

These advantages may, in one or more embodiments be synergistic, i.e.,the energy efficiency, reduced noise, etc. may be improved by using twoor more of the features and/or components together in the same airfilter systems.

In a first aspect, one or more embodiments of the air filter systemsdescribed herein may include: a tubesheet separating a housing into adirty air chamber and a clean air chamber, wherein the tubesheetcomprises an aperture placing the dirty air chamber in fluidcommunication with the clean air chamber, and wherein the housingcomprises an access panel located across the dirty air chamber from thetubesheet; a filter bag assembly located in the dirty air chamber, thefilter bag assembly comprising: a flange assembly comprising an interiorface and a tubesheet face facing the tubesheet, the flange assemblysurrounding the aperture in the tubesheet and comprising a clean airoutlet extending through the flange assembly, the clean air outlet influid communication with the aperture in the tubesheet; a cagecomprising a first cage end attached to the flange assembly andextending over a cage length to a second cage end distal from the flangeassembly, the cage defining a cage axis extending between the first cageend and the second cage end, the cage further comprising a plurality ofstruts extending away from the interior face of the flange assemblytowards the second cage end; and a filter bag comprising filter mediadefining an interior volume of the filter bag, wherein the filter bagextends from a first end to a second end, wherein a portion of thefilter media defines a bag opening at the first end of the filter bag;wherein the bag opening is attached to flange assembly, wherein the bagopening and the flange assembly form a seal around the clean air outletsuch that air entering the interior volume of the filter bag must passthrough the filter media of the filter bag or through the clean airoutlet of the flange assembly; a filter access port in the access panelof the housing, the filter access port comprising a cover movablebetween a closed position and an open position, wherein the cover closesthe filter access port when the cover is in the closed position andwherein the filter bag assembly can be inserted into or removed from thedirty air chamber through the filter access port when the cover is inthe open position; a seal located around the aperture in the tubesheetbetween the tubesheet face of the flange assembly and the tubesheet suchthat air passing through the aperture in the tubesheet must pass throughthe clean air outlet in the flange assembly before entering or leavingthe interior volume of the filter bag; a seal actuator proximate thefilter access port in the access panel, the seal actuator configured toapply a seal force on the second cage end through the second end of thefilter bag, wherein the seal force is directed along the cage axis andis transferred to the seal through the cage and the flange assembly; anda pulse generator located in the clean air chamber and configured todeliver pulses of air into the interior volume of the filter bag throughthe aperture in the tubesheet and the clean air outlet of the flangeassembly, the pulses of air passing through the aperture and the cleanair outlet before reaching the interior volume of the filter bag.

In a second aspect, one or more embodiments of a filter bag assembly asdescribed herein may include: a flange assembly comprising an interiorface and a tubesheet face, the flange assembly comprising a clean airoutlet extending through the flange assembly, wherein the clean airoutlet extends from a top end to a bottom end, wherein an outlet axisextends between the top end and the bottom end of the clean air outlet;a cage comprising a first cage end attached to the flange assembly andextending over a cage length to a second cage end distal from the flangeassembly, the cage defining a cage axis extending between the first cageend and the second cage end, the cage further comprising a plurality ofstruts extending away from the interior face of the flange assemblytowards the second cage end, wherein, in each cross-section taken in aplane transverse to the cage axis over a majority of the cage length,the plurality of struts define a triangle comprising a top vertex and apair of bottom vertices opposite the top vertex; and a filter bagcomprising filter media defining an interior volume of the filter bag,wherein the filter bag extends from a first end to a second end, whereina portion of the filter media defines a bag opening at the first end ofthe filter bag; wherein the bag opening is attached to the flangeassembly, wherein the bag opening and the flange assembly form a sealaround the clean air outlet such that air entering the interior volumeof the filter bag must pass through the filter media of the filter bagor through the clean air outlet of the flange assembly; wherein, whenthe cage is located in the filter bag, the filter media of the filterbag defines a pair of side surfaces and a bottom surface, wherein eachside surface of the pair of side surfaces comprises a top edge proximatethe top vertex of each triangle defined by the plurality of struts, andwherein each side surface of the pair of side surfaces comprises abottom edge distal from the top edge, wherein the bottom edges of theside surfaces are proximate the bottom vertices of each triangle definedby the plurality of struts, and wherein the bottom surface of the filtermedia extends between the bottom edges of the side surfaces.

In a third aspect, one or more embodiments of an air filter systemdescribed herein may include: a tubesheet separating a housing into adirty air chamber and a clean air chamber, wherein the tubesheetcomprises an aperture placing the dirty air chamber in fluidcommunication with the clean air chamber, and wherein the housingcomprises an access panel located across the dirty air chamber from thetubesheet; a filter guide in the dirty air chamber, the filter guideextending along a guide axis passing through the tubesheet and theaccess panel. The system includes a filter bag assembly mounted on thefilter guide and located in the dirty air chamber, the filter bagassembly comprising: a flange assembly comprising an interior face and atubesheet face facing the tubesheet, the flange assembly surrounding theaperture in the tubesheet and comprising a clean air outlet extendingthrough the flange assembly, the clean air outlet in fluid communicationwith the aperture in the tubesheet, wherein the clean air outletcomprises an elongated shape extending from a top end to a bottom end,wherein an outlet axis extends between the top end and the bottom end ofthe clean air outlet; a cage comprising a first cage end attached to theflange assembly and extending over a cage length to a second cage enddistal from the flange assembly, the cage defining a cage axis extendingbetween the first cage end and the second cage end, the cage furthercomprising a plurality of struts extending away from the interior faceof the flange assembly towards the second cage end, wherein, in eachcross-section taken in a plane transverse to the cage axis over amajority of the cage length, the plurality of struts define a trianglecomprising a top vertex and a pair of bottom vertices opposite the topvertex; and a filter bag comprising filter media defining an interiorvolume of the filter bag, wherein the filter bag extends from a firstend to a second end, wherein a portion of the filter media defines a bagopening at the first end of the filter bag; wherein the bag opening isattached to flange assembly, wherein the bag opening and the flangeassembly form a seal around the clean air outlet such that air enteringthe interior volume of the filter bag must pass through the filter mediaof the filter bag or through the clean air outlet of the flangeassembly; wherein, when the cage is located in the filter bag, thefilter media of the filter bag defines a pair of side surfaces and abottom surface, wherein each side surface of the pair of side surfacescomprises a top edge proximate the top vertex of each triangle definedby the plurality of struts, and wherein each side surface of the pair ofside surfaces comprises a bottom edge distal from the top edge, whereinthe bottom edges of the side surfaces are proximate the bottom verticesof each triangle defined by the plurality of struts, and wherein thebottom surface of the filter media extends between the bottom edges ofthe side surfaces; a filter access port in the access panel of thehousing, the filter access port comprising a cover movable between aclosed position and an open position, wherein the cover closes thefilter access port when the cover is in the closed position and whereinthe filter bag assembly can be inserted into or removed from the dirtyair chamber when the cover is in the open position, wherein, optionally,the cover acts on and forces the tubesheet face of the flange assemblyagainst the tubesheet when the filter bag assembly is mounted on thefilter guide and the cover is in the closed position; and a pulsegenerator located in the clean air chamber and configured to deliverpulses of air into the interior volume of the filter bag through theaperture in the tubesheet and the clean air outlet of the flangeassembly, the pulses of air passing through the aperture and the cleanair outlet before reaching the interior volume of the filter bag.

In a fourth aspect, one or more embodiments of an air filter system asdescribed herein may include: a tubesheet separating a housing into adirty air chamber and a clean air chamber, wherein the tubesheetcomprises an aperture placing the dirty air chamber in fluidcommunication with the clean air chamber, and wherein the housingcomprises an access panel located across the dirty air chamber from thetubesheet; a filter bag assembly located in the dirty air chamber, thefilter bag assembly comprising a flange assembly covering the aperturein the tube sheet, a cage comprising a first end attached to the flangeassembly, the cage extending away from the flange assembly to a secondend proximate the access panel, and a filter bag comprising a bagopening sealed within the flange assembly, wherein the cage is locatedin an interior volume of the filter bag with the second end of the cageproximate a closed end of the filter bag; an access port in the accesspanel proximate the second end of the cage, wherein the filter bagassembly passes through the access port during placement in and removalfrom the dirty air chamber; and means for forcing the flange assemblyagainst the tubesheet by applying a compression force on the second endof the cage, wherein the compression force acts on the second end of thecage through the filter bag.

In a fifth aspect, one or more embodiments of a method of sealing afilter bag over an aperture in a tubesheet of an air filter system asdescribed herein may include: positioning a filter bag assembly in adirty air chamber of an air filter system with a flange assembly of thefilter bag assembly located proximate the tubesheet, wherein a bagopening of a filter bag of the filter bag assembly is located over theaperture in the tubesheet, and wherein the flange assembly covers theaperture; and forcing the flange assembly against the tubesheet byapplying a compression force on a cage located in an interior volume ofthe filter bag, wherein the cage is attached to the flange assembly andextends away from the flange assembly towards a closed end of the filterbag; wherein air passing through the aperture in the tubesheet from thedirty air chamber must pass through the filter bag before reaching theaperture.

In a sixth aspect, one or more embodiments may involve use of atriangular filter bag in an air filter system comprising an array of twoor more of the triangular filter bags arranged generally horizontallywithin a dirty air chamber, wherein a bottom surface of each triangularfilter bag is oriented in a generally horizontal position.

In a seventh aspect, one or more embodiments of a triangular filter bagas described herein may include an opening, a closed end, a bodyextending from the opening to the closed end along a bag axis extendingbetween the opening to the closed end, and a substantially triangularend cap attached to the body at the closed end; wherein the bodycomprises filter media taking a tubular shape that defines an interiorvolume between the opening and the closed end, wherein the filter mediacomprises a closed end edge at the closed end of the bag and an openingedge at the opening of the bag; wherein the triangular end cap comprisesa bottom edge and two side edges extending away from the bottom edge,wherein the side edges meet at an apex of the triangular end cap that isdistal from the bottom edge; and wherein the filter media at the closedend edge of the body is sealed to the bottom edge, the apex, and the twoside edges of the triangular end cap.

In an eighth aspect, one or more embodiments of a filter bag asdescribed herein may include an opening, a closed end, a body extendingfrom the opening to the closed end along a bag axis extending betweenthe opening to the closed end, wherein the body comprises filter mediataking a tubular shape that defines an interior volume between theopening and the closed end, and wherein the filter bag comprises a bagsupport connector attached to an exterior of the body proximate theclosed end.

Use of any of the air filter systems, filter bag assemblies, and filterdescribed herein to remove particulate matter from dirty air is alsodescribed herein.

As used herein and in the appended claims, the singular forms “a,” “an,”and “the” include plural referents unless the context clearly dictatesotherwise. Thus, for example, reference to “a” or “the” component mayinclude one or more of the components and equivalents thereof known tothose skilled in the art. Further, the term “and/or” means one or all ofthe listed elements or a combination of any two or more of the listedelements.

It is noted that the term “comprises” and variations thereof do not havea limiting meaning where these terms appear in the accompanyingdescription. Moreover, “a,” “an,” “the,” “at least one,” and “one ormore” are used interchangeably herein.

The above summary is not intended to describe each embodiment or everyimplementation of the air filter systems and methods described herein.Rather, a more complete understanding of the invention will becomeapparent and appreciated by reference to the following Description ofIllustrative Embodiments and claims in view of the accompanying figuresof the drawing.

BRIEF DESCRIPTIONS OF THE VIEWS OF THE DRAWING

FIG. 1 is a perspective view of one illustrative embodiment of an airfilter system as described herein.

FIG. 2 is a side view of the air filter system depicted in FIG. 1.

FIG. 3 is a top view of the air filter system depicted in FIGS. 1 and 2.

FIG. 4A is a cross-sectional view of the air filter system of FIGS. 1-3taken along line 4A-4A in FIG. 3.

FIG. 4B is a cross-sectional view of the air filter system of FIG. 3taken along line 4B-4B in FIG. 3 when the system is out of service.

FIG. 4C is a cross-sectional view of the air filter system of FIG. 3taken along line 4B-4B in FIG. 3 during a pulse cleaning event.

FIGS. 4D-4F depict some alternative embodiments of filter guides andcorresponding guide apertures that may be provided in one or moreembodiments of air filter systems as described herein.

FIG. 4G is a cross-sectional view of the air filter system of FIGS. 1-3taken along line 4G-4G in FIG. 3.

FIG. 5 is a schematic diagram of components of one illustrativeembodiment of an air filter system as described herein illustrating theseal formed using a filter bag assembly as described herein.

FIG. 6A is a perspective view of a portion of a tubesheet, with oneillustrative embodiment of a filter bag assembly supported on oneillustrative embodiment of a filter guide as described herein.

FIG. 6B depicts one alternative embodiment of a bag support that may beprovided in one of more embodiments of air filter systems and filterbags as described herein.

FIG. 6C depicts another alternative embodiment of a bag support that maybe provided in one of more embodiments of air filter systems and filterbags as described herein.

FIG. 7A is a perspective view of one illustrative embodiment of aportion of an access panel including one illustrative embodiment ofcovers used to close access ports through which filter bag assemblies ofair filter systems are passed during removal and replacement.

FIG. 7B is a perspective view of alternative illustrative embodiments ofa portion of an access panel and covers used to close access ports, withthe covers including embossments shaped to complement the filter bagassemblies.

FIG. 8 is an exploded perspective view of the components depicted inFIG. 6.

FIG. 9A is a left side perspective view of one illustrative embodiment aflange assembly and cage used in one illustrative embodiment of a filterbag assembly as described herein.

FIG. 9B is an enlarged and exploded right side perspective view of theflange assembly of FIG. 9A.

FIG. 9C is an enlarged cross-sectional view of the flange assembly andcage depicted in FIG. 9A taken along line 9C-9C in FIG. 9A (only thosesurfaces at the plane defined by the cross-sectional line are depictedin FIG. 9C).

FIG. 10 is a diagram of one illustrative embodiment of a triangle formedby one illustrative embodiment of a filter bag used in an air filtersystem as described herein.

FIG. 11 is a diagram of another illustrative embodiment of a triangleformed by another illustrative embodiment of a filter bag used in an airfilter system as described herein.

FIG. 12 is a diagram depicting one illustrative example of a possiblearrangement of a pair of filter bags as depicted in FIG. 11.

FIG. 13 is a diagram of another illustrative embodiment of a triangleformed by another illustrative embodiment of a filter bag used in an airfilter system as described herein.

FIG. 14 is a perspective view of a portion of a tubesheet, with anotherillustrative embodiment of a filter bag assembly supported on anotherillustrative embodiment of a filter guide as described herein.

FIG. 15 is an enlarged partial cross-sectional view of the filter bagassembly of FIG. 14 depicting illustrative embodiments of the junctionsbetween the flange assembly components, filter, and tubesheet.

FIG. 16 is a cross-sectional view of another illustrative embodiment ofa filter bag assembly including an envelope-shaped filter bag supportedby a cage on a flange assembly as described herein.

FIG. 17 is a perspective view of one illustrative embodiment of atriangular filter bag that may be used in one or more embodiments of thefilter bag assemblies and air filter systems described herein.

FIG. 18 depicts components that may be used to construct theillustrative embodiment of the triangular filter bag depicted in FIG.17.

FIG. 19 is a schematic diagram illustrating relationships between thefeatures of the illustrative embodiment of the triangular end capdepicted in FIGS. 17-18.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In the following description of illustrative embodiments, reference ismade to the accompanying figures of the drawing which form a parthereof, and in which are shown, by way of illustration, specificembodiments. It is to be understood that other embodiments may be usedand structural changes may be made without departing from the scope ofthe present invention.

Referring to FIGS. 1-3, one illustrative embodiment of an air filtersystem is depicted generally at 10. The air filter system depicted inFIG. 1 is generally in the shape of a box and includes an upper wallpanel 16, and two pairs of opposite side wall panels 17 (one of which isvisible in FIG. 1). The air filter system 10 includes a dirty airconduit 11 for receiving dirty or contaminated air (i.e., air withparticulate matter therein) into the filter system 10. A clean airconduit 13 (see, e.g., FIG. 3) may be provided for removing clean orfiltered air from the filter system 10. The air filter system 10includes covers 70 closing access ports in the access panel 19 of theair filter system 10.

The air filter system may also include a hopper 18 to collectparticulate matter separated from the dirty air stream as describedherein. The hopper 18 may include sloped walls to facilitate collectionof the particulate matter and may, in some embodiments, include a drivenauger or other mechanism for removing the collected particulate matter.

The air filter system of FIG. 1 is depicted in a side elevation in FIG.2 and a top plan view in FIG. 3. The air filter system 10, as seen inFIGS. 2 and 3, includes connectors 86 in fluid communication with pulsegenerators (not depicted in FIGS. 1-3) as part of a pulse-jet cleaningsystem, with the pulse generators configured to direct a pulse of airinto the filter bags as described herein.

With reference to FIGS. 4A and 4G, the depicted air filter system 10includes filter bag assemblies including filter bags 40 and flangeassemblies 30 in a dirty air chamber 24 that is separated from a cleanair chamber 22 by a tubesheet 20. FIG. 4A is a cross-sectional view ofthe air filter system 10 taken along line 4A-4A in FIG. 3 and shows theinterior of the air filter system 10 (with the filter bags 40 locatedtherein being intact such that the support structure within the filterbags 40 is obscured from view). FIG. 4G is a cross-sectional view of theair filter system 10 taken along line 4G-4G in FIG. 3 (with thecross-sectional view depicting the interior volume of the filter bags 40such that a portion of the support structure within the filter bags 40is depicted). The filter bag assemblies are mounted on filter guides 60located in the dirty air chamber 24. In the depicted illustrativeembodiment, the filter guides 60 extend across the dirty air chamber 24from the tubesheet 20 to the access panel 19 of the air filter system.

The filter bags used in the air filter systems described herein may beconstructed of any suitable filter media in view of the particulatematter to be collected, airflow requirements, strength requirements,etc. Suitable filter bags may be constructed of filter media thatincludes one or more of polyester, polypropylene, aramid,polyester/polytetrafluoroethylene material in both woven and/or nonwovenconstructions, etc.

In one or more embodiments, the filter bags used in the filter bagassemblies described herein may be distinguished from filter cartridgesbased on their response to compression forces directed between thefilter bag opening and the second end of the filter bag, i.e., the endof the bag located opposite the bag opening. In the absence of anyextraneous support (such as, e.g., the internal cages described herein),filter bags used in the filter bag assemblies described herein would, inone or more embodiments, deform under a compressive force of 5 Newtons(approx. 1.1 pound-force) directed along a line extending through thebag opening to the distal/closed end of the filter bag (e.g., along thecage axis 51 depicted in FIG. 4A). In addition to deforming, one or moreembodiments of the filter bags used in the filter bag assembliesdescribed herein, transmit essentially none of such a compressive force.A filter cartridge would, in contrast, not significantly deform andwould transmit most, if not all, of such a compressive force. Theflexibility that is the source of the inability of the filter bags usedin the filter bag assemblies and air filter systems described herein totransmit compressive forces is, however, the source of the filter bags'ability to rapidly accelerate (sometimes referred to as “snap”) outwardto remove particulate matter collected on the exterior of the filtermedia in response to a cleaning pulse.

At the tubesheet end, each of the filter bag assemblies includes aflange assembly 30. The flange assembly 30 includes an interior face 35facing the dirty air chamber 24 and a tubesheet face that seals againstthe dirty air chamber side of the tubesheet 20. Each of the flangeassemblies 30 surrounds an aperture in the tubesheet 20 through whichclean air can pass from the interior of a filter bag assembly into theclean air chamber and through which a pulse of air can pass into theinterior of a filter bag during a pulse cleaning event.

Although the flange assemblies 30 on each of the filter bag assemblieswill be described in more detail herein, the depicted illustrativeembodiment of flange assemblies 30 seen in FIG. 4A includes a base 32including the tubesheet face of the flange assembly 30 and a clamp 34configured to attach to the base 32 on the interior face of the flangeassembly 30. In such an embodiment, the clean air outlet extends throughthe base 32 and the clamp 34, with the bag opening of the filter bag 40being retained between the clamp 34 and the base 32 on the interior faceof the flange assembly 30.

The illustrative embodiment of air filter system 10 as depicted in FIG.4A also includes pulse generators 80 located in the clean air chamber22. The pulse generators 80 are configured to deliver pulses of air intothe interior volumes of the filter bags 40 to drive particulate matterthat has accumulated on the filter bags 40 during use of the filterbags, with the dislodged particulate matter preferably falling into thehopper 18 located below the filter bags 40. In one or more embodiments,the pulse generators 80 may be described as having elongated shapes thatextend along pulse generator axes 81 as seen in, e.g., FIG. 4A.Pressurized air (or any other suitable gas) is delivered to the pulsegenerators through connectors 86 that, in the depicted embodiment,extend outside of the clean air chamber 22 for connection to a pulsecleaning system including one or more sources of pressurized gas (e.g.,air), valves and a control system. Illustrative embodiments of pulsecleaning systems may be found in, e.g., U.S. Pat. No. 4,218,227 (Frey),U.S. Pat. No. 5,562,746 (Raether), U.S. Pat. No. 6,090,173 (Johnson etal.), U.S. Pat. No. 6,902,592 (Green et al.), U.S. Pat. No. 7,641,708(Kosmider et al.), and U.S. Pat. No. 8,075,648 (Raether).

Also depicted in connection with the illustrative embodiment of airfilter system 10 are pulse collectors 84 which, as will be describedherein, may be attached to the flange assemblies 30 of the filter bagassemblies. In other embodiments, the pulse collectors 84 may beattached to the tubesheet 20. Regardless of the structure to which theyare attached, the pulse collectors 84 are configured to direct pulsedair emitted from the pulse generators 80 into the interior volumes ofthe filter bags 40 during the pulse cleaning process.

FIGS. 4B and 4C are cross-sectional views taken along line 4B-4B in FIG.4A, with FIG. 4B being taken when the air filter system 10 is either notin use or is being used to filter dirty air being delivered into thedirty air chamber 24 through inlet 11. FIG. 4C depicts the filter bag 40relative to the other structures of the filter bag assembly during apulse cleaning event when pressurized air (or other gas) is deliveredinto the interior volume of the filter bag 40 as described herein.

FIG. 4B depicts a portion of the dirty air chamber side of the tubesheet20 with flange assembly 30 located thereon. As discussed herein, thedepicted illustrative embodiment of flange assembly 30 includes a base32 and a clamp 34, with the bag opening of the filter bag 40 beingretained between the clamp 34 and the base 32 such that air can enterthe interior volume of filter bag 40 only by passing through the filtermedia used to construct filter bag 40 or by passing through the cleanair outlet 36 of the flange assembly 30.

The filter bag assembly as seen in FIGS. 4B and 4C includes a cage usedto hold the filter bag 40 in a triangular shape (with the cage beingseen in the cross-sectional view of FIG. 4G). In the depictedillustrative embodiment, the cage includes a first cage end attached tothe flange assembly 30, with the cage extending away from the flangeassembly 30 over a cage length along a cage axis 51 to a second cage enddistal from the flange assembly 30. In the depicted illustrativeembodiment, the second cage is located proximate the access panel 19 ofthe air filter system 10.

In the depicted illustrative embodiment of the filter bag assembly, thecage includes a plurality of struts that extend away from the interiorface of the flange assembly 30 towards the second cage end proximate theaccess panel 19 of the air filter system 10. The plurality of strutsdefine a triangular shape such that, in each cross-section taken in aplane transverse to the cage axis 51 over a majority of the length ofthe cage, the plurality of struts define a triangle having a top vertexand a pair of bottom vertices opposite the top vertex.

In the depicted illustrative embodiment, the cage includes a top strut52 and a pair of bottom struts 54 and 56. The top strut 52 defines a topvertex of the triangles defined by the plurality of struts, while thepair of bottom struts 54 and 56 defined the bottom vertices of thetriangles defined by the plurality of struts. The depicted illustrativeembodiment of the cage also includes a series of braces 53 extendingfrom the top strut 52 to each of the bottom struts 54 and 56 to provideadditional support to the filter bag 40 at selected locations along thelength of the cage.

When the cage is located in the filter bag 40, the filter media of thefilter bag 40 may be described as defining a pair of side surfaces 42and a bottom surface 44. Each of the side surfaces 42 includes a topedge proximate the top vertex (as defined by the top strut 52) of eachtriangle defined by the plurality of struts. Moreover, each side surface42 also includes a bottom edge distal from the top edge of the sidesurface 42. With reference to FIG. 4B, the bottom edge of the right sidesurface 42 is defined by the right side bottom vertex (as defined bybottom strut 54) of each triangle defined by the plurality of struts,while the bottom edge of the left side surface 42 is defined by the leftside bottom vertex (as defined by bottom strut 56) of each triangledefined by the plurality of struts.

Because the filter bags used in the filter bag assemblies of air filtersystems as described herein are made of generally flexible filter media,the top edges and bottom edges of the triangular-shaped filter bags maynot be particularly distinct, i.e., the edges may not form a singleline. It will, however, be understood that the edges may have a widtharound which the filter media extends when moving from the side surfaces42 to the bottom surface 44 around the bottom struts 54 and 56 and/orwhen moving from one side surface 42 to the opposite side surface overthe top strut 52. Regardless of that lack of distinctiveness, the edgeswill be understood as conforming generally to the shape of the strutsused to define the different vertices of the triangles.

The triangular shapes defined by the plurality of struts in theillustrative embodiment of the cage as seen in FIGS. 4B and 4C are onlyone example of the triangular shapes that may be used in connection withfilter bag assemblies and air filter systems as described herein. Ingeneral, however, one or more embodiments of the filter bag assembliesdescribed herein may be described as having a bottom surface 44 offilter media having a width measured between the bottom edges of theside surfaces 42 (as defined by the bottom struts 54 and 56) that isless than a height of either of the side surfaces 42 as measured betweentheir top edges and bottom edges (where the top edges are defined by thetop strut 52 and the bottom edges are defined by the bottom struts 54and 56). In one or more embodiments, the width of the bottom surface 44may be 50% or less, 40% or less, 30% or less, 20% or less, 15% or less,12% or less, 10% or less, 8% or less, or 5% or less of the height ofeither side surface 42 of the pair of side surfaces. At a lower end, thewidth of the bottom surface may be 4% or more, 5% or more, 6% or more,8% or more, 10% or more, 12% or more, 15% or more of the height ofeither side surface of the pair of side surfaces. The width and heightas discussed herein are measured transverse to the cage axis 51, i.e.,as seen in, e.g., FIG. 4B.

Other features depicted in the cross-sectional views of FIGS. 4B and 4Cinclude filter guide 60 which, in the depicted illustrative embodiment,extends from the tubesheet 20 to the access panel 19 of the dirty airchamber 24. In the depicted illustrative embodiment, the filter guide 60defines a guide axis 61 passing through the tubesheet 20 and the accesspanel 19. The depicted guide axis 61 is aligned with the cage axis 51and, although, the two axes 51 and 61 may be parallel with each other, aperfectly parallel arrangement is not required.

Filter guide 60 includes an entry end 63 at which the guide aperture 62on the flange assembly 30 can be threaded, guided, or otherwise directedonto the filter guide 60 so that the flange assembly 30 can be supportedon the filter guide 60. In one or more embodiments, the entry end 63 ofthe filter guide 60 may be located closer to the access panel 19 of theair filter system than the tubesheet 20 against which the flangeassembly 30 is forced as described herein.

Although the filter guide 60 extends from the tube sheet 20 to theaccess panel 19 in some of the depicted illustrative embodimentsdescribed herein, in one or more alternative embodiments, the filterguide 60 may only extend partially across the dirty air chamber suchthat, e.g., the filter guide 60 may terminate at a location short of theaccess panel 19 or even short of the tube sheet 20. In one alternativeembodiment, for example, the filter guide 60 may extend from thetubesheet 20 towards the access panel 19 but terminate short of theaccess panel 19.

The filter guide 60 is located within a guide aperture 62 formed in theflange assembly 30. The combination of the filter guide 60 and the guideaperture 62 formed in the flange assembly 30 provides support to theflange assembly 30 during insertion and removal of a filter bag assemblyfrom the dirty air chamber 24 of the air filter system 10. Inparticular, it may be preferred that the filter guide 60 and guideaperture 62 allow for translational or sliding movement of the flangeassembly 30 through an access port in the access panel 19 to thetubesheet 20. Although the depicted filter guide 60 and guide aperture62 in the flange assembly 30 have similar shapes, any suitablecombination of shapes for both the filter guide and the guide aperturemay be used.

Some alternative embodiments of filter guides and guide apertures aredepicted in FIGS. 4D-4F. In FIG. 4D, the filter guide 60′ has a T-shapedprofile and the guide aperture 62′ in flange assembly 30′ has acomplementary shape configured to accept the filter guide 60′. In FIG.4E, the filter guide 60″ has an inverted T-shaped profile and the guideaperture 62″ in flange assembly 30″ has a complementary shape configuredto accept the filter guide 60″. In FIG. 4F, the filter guide 60′″ has around profile and the guide aperture 62′″ in flange assembly 30′″ has acomplementary shape configured to accept the filter guide 60′″. Manyother alternative shapes for filter guides and guide apertures couldalso be provided.

In addition to providing support to the flange assembly 30 in a verticaldirection, the combination of filter guide 60 and guide aperture 62 may,in one or more embodiments, also serve to limit or prevent rotation ofthe flange assembly around the guide axis 61 so that proper alignment ofthe flange assembly 30 on the tubesheet 20 may be achieved. To limit orprevent such rotation, the filter guide 60 and guide aperture 62 on theflange assembly 30 may have a noncircular shapes, with the tri-lobed andT-shaped examples of the depicted illustrative embodiments providingexamples of only some noncircular shapes that may limit or preventrotation of the flange assembly 30 relative to the guide axis 61.

In one or more embodiments, the filter guide 60 may include a dust coverto prevent accumulation of particulate matter on the filter guide 60that could be dislodged during removal of the filter bag assembly (e.g.,as the flange assembly 30 moves from the tubesheet 20 towards the accesspanel 19).

Other features depicted in the cross-sectional views of FIGS. 4B and 4Cinclude the clean air outlet 36 provided in the flange assembly 30 whichallows both clean air to exit the interior volume of the filter bags 40and also allows for pulses of air or other gases to enter the interiorvolume during a pulse cleaning process. In one or more embodiments, theclean air outlet may be described as having an elongated shape thatextends from a top end (closest to the top strut 52) and a bottom end(closest to the bottom struts 54 and 56). The top end and the bottom endof the clean air outlet 36 may further be described as defining anoutlet axis 31 that extends between the top and bottom ends of the cleanair outlet 36. In one or more embodiments, a projection of the outletaxis 31 along the cage axis 51 passes between the pair of bottomvertices of the triangles defined by the plurality of struts (wherethose bottom vertices are defined by the bottom struts 54 and 56).Further, the projection of the outlet axis 31 passes through the topvertex (as defined by the top strut 52) of the triangles defined by theplurality of struts.

Although not depicted in FIGS. 4B and 4C, will be understood thattubesheet 20 includes a tubesheet aperture formed therethrough that isat least as large as the clean air outlet 36 provided in the flangeassembly 30 such that the tubesheet aperture does not restrict airflowthrough the clean air outlet 36 into or out of the interior volume ofthe filter bag 40. Furthermore, the tubesheet aperture may also bedescribed as having a size that is smaller than the flange assembly 30such that the flange assembly 30 can close or seal the tubesheetaperture such that air passing between the clean air chamber 22 anddirty air chamber 24 must pass through a clean air outlet 36 when theair filter system 10 is operational.

The cross-sectional views of FIGS. 4B and 4C also depicts the alignmentbetween pulse generators 80 and the clean air outlet 36 of the flangeassemblies 30 in the depicted illustrative embodiment of air filtersystem 10. In particular, the pulse generators 80 may be aligned withthe clean air outlet 36. Even more particularly, the pulse generatoraxis 81 may be aligned with the outlet axis 31 when viewed along thecage axis 51 as seen in FIGS. 4B and 4C.

The views of FIGS. 4B and 4C further depict the ports 82 of pulsegenerator 80. In particular, the ports 80 to face the clean air outlet36 and the aperture in the tubesheet 20. Air delivered through the ports82 of the pulse generator 80 passes through those ports and into theclean air outlet 36 formed in flange assembly 30.

Because the filter bags used in air filter systems as described hereinhave generally triangular shapes, various features may be incorporatedinto the ports 82 of the pulse generators 82 facilitate the pulsecleaning process. For example, in one or more embodiments, the ports 82closer to the bottom end of the clean air outlet 36 (i.e., closer to thebottom 44 of the filter bag 40) may be larger in size than ports 82located closer to the top end of the clean air outlet 36 (i.e., closerto the top edges of the sides 42 of the filter bag 40). Alternatively,or in addition, the spacing between ports 82 may vary along the pulsegenerator axis 81. For example, the spacing between the ports 82 locatedcloser to the bottom end of the clean air outlet 36 may be smaller thanthe spacing between the ports 82 located closer to the top end of theclean air outlet 36. Such variations in size and/or spacing of the ports82 may facilitate the pulse cleaning process by providing more air andor higher pressures within the filter bag 40 proximate the bottomsurface 44.

A comparison of FIGS. 4B and 4C illustrates the beneficial effects ofthe triangular-shaped filter bags described herein with respect toparticular loading and pulse cleaning. In particular, as seen in FIG. 4Bthe triangular shaped filter bag 40 includes a bottom surface 44 thatfaces downwardly away from the dirty air inlet 11 into dirty air chamber24 (see, e.g., FIG. 4A). Particulate matter introduced into the dirtyair chamber 24 above the triangular filter bag 40 does not, therefore,impinge directly on or, under the force of gravity alone, collect on thebottom surface 44 of the filter bag 40. This improves particulateloading performance of the filter bag 40.

Improvements in pulse cleaning performance are also provided by thetriangular-shaped filter bag 40 because particulate matter that doescollect on the bottom surface 44 of the filter bag 40 is directeddownwardly away from the bottom surface 44 during pulse cleaning. Withreference to FIG. 4C, the bottom surface 44 of the filter bag 40 isforced outwardly/downwardly during pulse cleaning. By virtue of thenature of pulse cleaning, that outward/downward movement of the bottomsurface 44 is a result of rapid acceleration which imparts a force toany dislodged particulate matter released from the bottom surface 44,with the vector of that pulse cleaning force being generally alignedwith the force of gravity to enhance movement of any dislodgedparticulate matter into a collection area such as, e.g., hopper 18 ofair filter system 10.

In addition to the beneficial effects of the bottom surface 44 of thetriangular-shaped filter bags 40 of air filter systems as describedherein, the side surfaces 42 of the filter bags 40 are also rapidlyaccelerated outward during pulse cleaning as seen in the changedpositions of the sides 42 of filter bag 40 between FIGS. 4B and 4C. Asdiscussed herein, such movement of the sides 42 of the triangular-shapedfilter bags 40 provides many of the same advantages in pulse cleaningperformance associated with conventional envelope-shaped filter bagshaving vertical sides.

FIG. 5 is a simplified schematic diagram of components of theillustrative embodiment of air filter system 10 depicting oneillustrative embodiment of a seal formed using a filter bag assembly inan air filter as described herein. In the depicted illustrativeembodiment, the filter bag assembly includes a flange assembly 30′ and acage 50′ attached to the flange assembly 30′.

A filter bag 40′ is attached to the filter bag assembly, with bagopening 41′ being sealed against flange assembly 30′ and the cage 50′located within the interior volume defined by the filter bag 40′. Forreference, clean air outlet 36′ extends along an outlet axis 31′ in amanner similar to the outlet axis 31 depicted in, e.g., FIGS. 4A-4C.

Cage 50′ defines a cage axis 51′ that extends through clean air outlet36′ defined in flange assembly 30′. Cage 50′ may also be described asincluding a first cage and attached to the flange assembly 30′ and asecond cage end distal from the flange assembly 30′ along the cage axis51′. The second cage and of the cage 50′ may also be described as beingproximate the second end 43′ of the filter bag 40′.

Tubesheet 20′ includes aperture 26′ formed through the tubesheet 20′.Clean air chamber 22′ and dirty air chamber 24′ are also indicated inFIG. 5, with the two chambers being separated by the tubesheet 20′.Flange assembly 30′ is positioned over the aperture 26′ in tubesheet 20′such that air passing into and out of the interior volume of the filterbag 40′ from the clean air chamber 22′ passes through the aperture 26 ‘and the clean air outlet 36’ in the flange assembly 30′.

FIG. 5 also depicts the access panel 19′ located opposite tubesheet 20′across the dirty air chamber 24′. Access port 74′ is provided in accesspanel 19′ to allow for removal and replacement of the filter bagassembly (including flange assembly 30′, filter bag 40′, and cage 50′attached to flange assembly 30′ and located within the interior volumeof the filter bag 40′). Access port 74′ is closed by cover 70′ to sealthe dirty air chamber 24′ during operation of the air filter system.

Also depicted in FIG. 5 is a seal 38′ located between a tubesheet faceof the flange assembly 30′ and the tubesheet 20′. Seal 38′ is locatedaround aperture 26′ in tubesheet 20′ as well as being located aroundclean air outlet 36′ in flange assembly 30′. Seal 38′ ensures that airpassing into the interior volume of the filter bag 40′ must pass eitherthrough the filter media forming filter bag 40′ (during, e.g.,filtering) or the clean air outlet 36′ and aperture 26′ in tubesheet 20.In other words, the seal 38′ between flange assembly 30′ and tubesheet20′ prevents air (and preferably any particulate matter) from passingbetween the tubesheet face of the flange assembly 30′ and the tubesheet20′ during operation of an air filter system as described herein.

In one or more embodiments, seal 38′ may be formed by compressionbetween the flange assembly 30′ and the tubesheet 20′. In one or moreembodiments, a seal actuator may be provided to apply a seal force onthe cage 50′ of the filter bag assembly. In such embodiments, the sealforce is preferably directed along the cage axis 51 towards thetubesheet 20′. In one or more embodiments, the seal force may bedescribed as being directed through the second end 43′ of the filter bag40′ and further being transferred to the seal 38′ through the filter bag40′, cage 50′, and flange assembly 30′. In particular, the cover 70′,which functions as the seal actuator in the depicted illustrativeembodiment, acts on the second end 43′ of the filter bag 40′ which, inturn, acts on the second cage end of the cage 50′, with the cage 50′transferring that force to the flange assembly 30′ by virtue of itsattachment to the flange assembly 30′.

Seal 38′ may be constructed of any suitable material and/or structures.Although many seals may be formed by compression of one or moreresilient and/or elastomeric materials (in, e.g., O-rings, gaskets,etc.), other seal constructions may also be used to form the requiredseal between the flange assembly and the tubesheet in air filter systemsas described herein when the flange assembly is subjected to acompression force (e.g., knife edge seals, radial seals, axial seals,etc.).

FIG. 6A is a perspective view of a portion of the tubesheet 20, with theillustrative embodiment of a filter bag assembly including a filter bag40 supported on the illustrative embodiment of filter guide 60. Asdiscussed herein, the filter bag assembly, including flange assembly 30and filter bag 40 are supported on the filter guide 60, with the flangeassembly 30 forming a seal with the tubesheet 20.

In one or more embodiments of the filter bags and air filter systemsdescribed herein, a bag support may be provided proximate the second endof the filter bag, i.e., the end of the filter bag distal from theflange assembly, with the bag support configured to prevent or limitsagging of the filter bag assembly at the second end of the filter bagdue to, e.g., the weight of the cage located in the filter bag. In oneor more embodiments of the filter bags, filter bag assemblies, and/orair filter systems described herein, the bag support may be provided onfilter bag itself, as a part of the air filter system, and/or includecomponents provided as a part of the filter bag and as a part of the airfilter system.

The filter bag assembly depicted in FIG. 6A includes one illustrativeembodiment of a bag support in the form of a bag support connector 46attached to the filter bag 40 proximate the second end 43 of the filterbag 40 and a chamber connector 64 that is positioned in the dirty airchamber proximate the access panel 19 of the housing. In the depictedembodiment the chamber connector 64 is located on the filter guide 60although such positioning is not required. The bag support connector 46and the chamber connector 64 are configured to interlock with each otherto support the second end of the filter bag 40 in the dirty air chamber(with the first end of the filter bag 40 being supported by the flangeassembly 30 in cooperation with the filter guide 60 as describedherein).

In the embodiment of a bag support as depicted in FIG. 6A, the bagsupport connector 46 is in the form of a loop while the chamberconnector 64 is in the form of a hook, with the loop 46 connecting tothe hook 64 to support the second end 43 of the filter bag 40. Manyvariations are, of course possible. For example, the bag supportconnector 46 on the filter bag 40 may be in the form of a hook while thechamber connector 64 is in the form of a loop or aperture configured toreceive the hook.

FIG. 6B depicts one alternative embodiment of a bag support that may beused to prevent or limit sagging of a filter bag assembly at the secondend of the filter bag. In the depicted embodiment, the bag supportincludes the chamber connector 64 on filter guide 60 similar to thatdepicted in FIG. 6A which, in the depicted embodiment, is attached toaccess panel 19″ (with cover 70″ closing the access opening in theaccess panel 19″ as described herein). The embodiment of a bag supportdepicted in FIG. 6B includes a sling 47″ that may, for example wraparound the bag 40″, with the sling 47″ forming a loop that is configuredto connect to the hook 64 on filter guide 60. In one or moreembodiments, the sling 47″ may be attached to the filter bag 40″ usingone or more of, e.g., sewing, adhesives, etc. such that the sling 47″ isreplaced with the filter bag 40″. Alternatively, the sling 47″ may beseparate, e.g., unattached, to the filter bag 40″ such that the sling47″ can be re-used with two or more different filter bags 40″.

FIG. 6C depicts yet another alternative embodiment of a bag support thatmay be used to prevent or limit sagging of a filter bag assembly at thesecond end of a filter bag. In the depicted embodiment, the bag support46′″ is in the form of a surface provided proximate the bottom of thefilter bag 40′″. The bag support 46′″ may be attached to the accesspanel 19′″ and may be accessed through the opening in the access panel19′″ that is closed by cover 70′″. In one or more embodiments, the bagsupport 46′″ may be moved downward (away from the bag axis 51) to assistwith replacement of the filter bag 40′″. Movement of the bag support46′″ may include one or both of translational and rotational movement ofthe bag support 46′″.

FIG. 7A is a perspective view of one illustrative embodiment of aportion of a access panel 19 including one illustrative embodiment of acover 170 used to close a filter access port 174 formed in the accesspanel 19 through which filter bag assemblies including filter bags 140can be removed from and inserted into the dirty air chamber 24 of theair filter system 10. The illustrative embodiment of cover 170 includesa latch 172 and catch 173 to secure the cover 170 in a closed position(see the covers 170 to the right of the open cover 170). The covers 170may be connected to the access panel 19 for rotation about a hinge axis171 such that the covers 170 can be moved from a closed position to anopen position in which filter bag assemblies can be inserted into orremoved from the dirty air chamber through access port 174.

Rotation of the cover 170 about hinge axis 171 moves the cover 170 toits closed position in which cover 170 covers filter access port 174.When in the closed position, the cover 170 may, in addition to closingfilter access port 174, function as a seal actuator such that the cover170 also acts on the second ends 143 of the filter bags 140 to force anattached flange assembly against a tubesheet to form a seal as describedherein. The forces provided by the cover 171 acting as a seal actuatorwhen closed may be described as acting along the cage axes 151.

FIG. 7B is a perspective view of the access panel 19 of FIG. 7Aincluding an alternative illustrative embodiment of a cover 170′ used toclose a filter access port 174 formed in the access panel 19 throughwhich filter bag assemblies including filter bags 140 can be removedfrom and inserted into the dirty air chamber of the air filter systemincluding access panel 19. This illustrative embodiment of cover 170′also includes a latch 172 and catch 173 to secure the cover 170′ in aclosed position (see the cover 170′ to the right of the open cover170′). The covers 170′ may also be connected to the access panel 19 forrotation about a hinge axis 171 such that the covers 170′ can be movedfrom a closed position to an open position in which filter bagassemblies can be inserted into or removed from the dirty air chamberthrough access port 174.

Rotation of the covers 170′ about hinge axis 171 moves the covers 170′to their closed positions in which covers 170′ close filter access port174. When in the closed position, the covers 170′ may, in addition toclosing filter access port 174, function as seal actuators such that thecovers 170′ also act on the second ends 143 of the filter bags 140 toforce an attached flange assembly against a tubesheet to form a seal asdescribed herein. The forces provided by the covers 170′ acting as sealactuators when closed may be described as acting along the cage axes151.

An additional feature depicted in covers 170′ are the embossments 176provided in cover 170′. The embossments 176 may, in one or moreembodiments, have shapes that are complementary to the shape of the ends143 of the filter bags 140. Such embossments may provide advantages suchas, for example, additional stability to the filter bag assembliesproximate the access panel 19, more uniform force distribution over thesecond ends 143 of the filter bags 140 and, therefore, over the cageslocated within the filter bags 140 in filter bag assemblies as describedherein, verification of proper installation of the filter bag assemblies(such that, for example, the bottom surfaces of triangular filter bagsare properly oriented in a dirty air chamber), etc. In embodiments thatinclude such embossments, a bag support configured to support the secondend of the filter bag (as discussed above in connection with, e.g.,FIGS. 6A-6C) may be helpful in ensuring that the second ends 143 of thefilter bags 140 are properly positioned as the covers 170′ are closed.

FIG. 8 is an exploded diagram of the filter bag assembly of FIG. 6depicting the filter bag 40 removed from the cage 50 and, in addition,the clamp 34 of flange assembly 30 being removed from the base 32. Asdiscussed in connection with other embodiments of filter bags describedherein, filter bag 40 includes an opening 41 at its first end and a bagsupport connector 46 proximate the second end of the filter bag 40.

FIG. 8 also depicts the cage 50 including a top strut 52 and pair ofbottom struts 54 and 56, all of which are, in the depicted embodiment,aligned with the cage axis 51. Cage 50 also includes braces 53 extendingbetween the top strut 52 and the bottom struts 54 and 56. At thelocation of each of the side braces 53, bottom braces 55 may also beprovided between the bottom struts 54 and 56 to maintain the triangularshape of the cage 50 by properly positioning the bottom struts 54 and56.

Another feature depicted in connection with FIG. 8 is that a pulsecollector 84 may be attached to the flange assembly 30, in particular,to the base 32 of the depicted flange assembly 30. As a result, removalof the filter bag assembly would include removal of the pulse collector84 along with the flange assembly 30, cage 50 and filter bag 40. In sucha system, the tubesheet aperture 26 in tubesheet 20 is preferably sizedto accommodate the pulse collector 84. Furthermore, a seal maypreferably be provided on the tubesheet face of the flange assembly toseal the junction between the flange assembly 30 and the tubesheet 20 asdescribed herein.

FIGS. 9A-9C depict another illustrative embodiment of components of afilter bag assembly as described herein including a flange assembly 130and cage 150 attached to the flange assembly 130. The filter bag thatwould be provided over the cage 150 with an opening attached to theflange assembly 130 is not depicted in FIGS. 9A and 9B for clarity.

The flange assembly 130 depicted in FIGS. 9A-9C includes a clamp 134 andbase 132, with the clamp 134 and base 132 shown as separated from eachother along the cage axis 151 in FIG. 9B. The depicted flange assembly130 also includes a clean air outlet 136 that is elongated along anoutlet axis 131. A guide aperture 162 is provided at the top of theflange assembly 130 for use with a filter guide as described inconnection with other illustrative embodiments presented herein. Aportion of seal 138 which is located on the tubesheet face of the flangeassembly 130 and which extends around the clean air outlet 136 is alsodepicted in FIGS. 9A-9C.

The cage 150 depicted in FIGS. 9A-9B includes a top strut 152 and a pairof bottom struts 154 and 156, all of which are, in the depictedembodiment, aligned with the cage axis 151. Cage 150 also includesbraces 153 extending between the top strut 152 and the bottom struts 154and 156. The depicted cage 150 also includes an intermediate strut 157aligned with the cage axis 151. The additional intermediate strut 157may provide further structural integrity to the cage 150 and may, in oneor more embodiments, enhance the uniformity of any seal forcetransferred through the cage 152 the flange assembly 132 form a seal asdescribed herein.

Another feature depicted in FIGS. 9A-9C is a pulse collector 184attached to the flange assembly 130. In one or more embodiments, removalof a filter bag assembly including flange assembly 130 and cage 150would also remove the pulse collector 184.

An enlarged cross-sectional view of a portion of the components depictedin FIG. 9A is provided in FIG. 9C, with the tubesheet 120 and tubesheetaperture 126 also being depicted in FIG. 9C. It should be understoodthat only those components actually visible in the plane of thecross-sectional view are depicted in FIG. 9C. Both the outlet axis 131and the cage axis 151 are depicted in FIG. 9C for reference.

With reference to FIG. 9C, the base 132 and clamp 134 of the flangeassembly 130 are seen in FIG. 9C along with the bag opening 141 offilter bag 140 being clamped between the base 132 and clamp 134. Cleanair outlet 136 formed in the base 132 of the flange assembly providesfor passage of air into or out of the interior volume defined by thefilter bag 140 as described herein.

In one or more embodiments, the filter media forming the filter bagopening 141 may, itself, provide for seal between the flange assemblyand the filter bag opening 141 that is sufficient to prevent leakagesuch that air entering or leaving the interior volume of the filter bag140 must pass through the filter media of the bag or the clean airoutlet 136. Alternatively, additional seals and/or sealing material maybe provided to prevent unwanted passage of air between the flangeassembly and the filter bag opening 141. For example, the bag opening141 may include a compressible seal/cuff (similar to that found in,e.g., cuff 649 of filter bag 640 depicted in FIGS. 17-19) that mayenhance sealing of the bag opening 141 between the base 132 and theclamp 134 to prevent the passage of air and/or particulate matterthrough the interface between the base 132, the clamp 134, and filterbag opening 141.

The tubesheet face of the clamp assembly (i.e., the face of base 132facing tubesheet 120) acts on seal 138 which is located between base 132and tubesheet 122 prevent the passage of air and/or particulate matterbetween the flange assembly base 132 and the tubesheet 120 duringoperation of an air filter system. Pulse collector 184 is depicted asbeing attached to the base 132 of the flange assembly in thisillustrative embodiment.

As discussed herein, the filter bags used in the filter bag assembliesof air filter systems described herein are made of generally flexiblefilter media, the filter bags may not form particularly distincttriangles when viewed in cross-section. In general, however, thetriangular-shaped filter bags and their associated cages can bedescribed using the geometry of triangles with an understanding that theedges, sides, and vertices of such triangles will be generallyapproximated by the triangular cages and filter bags fitted thereon.

With that understanding, reference is made to FIGS. 10-13 in whichvarious triangular-shaped bag constructions that may be used in one ormore embodiments of filter bag assemblies and air filter systems usingthe filter bag assemblies as described herein.

The idealized triangular-shaped bag 140 depicted in FIG. 10 is, in manyrespects, similar to the triangular-shaped bag 40 discussed herein withrespect to various embodiments of the filter bag assemblies and airfilter systems described above. The triangular-shaped bag 140 includes atop vertex 145 and a pair of bottom vertices 146 and 147. A pair of sidesurfaces 142 extend between the top vertex 145 and each of the bottomvertices 146 and 147. A bottom surface 144 extends between the bottomvertices 146 and 147.

To further illustrate the difference between an idealizedtriangular-shaped defined by one or more embodiments of filter bags asdescribed herein and the actual shapes taken by filter bags located oncages that provide the triangular shapes, the struts of cage 150 as seenin FIGS. 9A-9B are included in FIG. 10 along with cage axis 151 (whichextends perpendicularly out of the paper on which FIG. 10 is located).In particular, top strut 152, bottom struts 154 and 156, andintermediate struts 157 are depicted inside filter bag 140 in FIG. 10.It should be noted that top strut 152 may, as depicted in thisillustrative embodiment be formed as a composite of two members. Such aconstruction may provide filter bag 140 with a small flat surface alongits top edge. Reference can be had to, e.g., FIGS. 7A and 7B wherefilter bag 140 has a relatively small flat top edge as a result of asomewhat widened top strut. Regardless of the slight deviations from aperfect triangle, it can be seen that the side surfaces 142 and bottomsurface 144 of the filter bag 140 take on a generally triangular shapeas described herein.

The bottom surface 144 may be described as having a width wb extendingbetween the bottom vertices 146 and 147. The left side surface 142 maybe described as having a height s1 measured between the top vertex 145and bottom vertex 147. The right side surface 142 may be described ashaving a height s2 measured between the top vertex 145 and bottom vertex146. As discussed herein the width of the bottom surface (wb) ispreferably less than the height of either of the side surfaces (s1 ors2).

Although not required, the depicted triangular-shaped bag 140 forms atriangle that may be described as being an acute triangle and,optionally, an isosceles triangle (in which s1=s2). In the case of anisosceles triangle, the axis 101 depicted in FIG. 10 may be described asbeing an altitude of the triangle formed by the filter bag 140.

The triangular-shaped bag 140 may further be described with respect tothe angle formed by the side surfaces 142. In particular, the angle α(alpha) formed by side surfaces 142 at vertex 145 may be selected suchthat the width (wb) of the bottom surface 144 has a selectedrelationship with the heights of the side surfaces 142. In one or moreembodiments, the angle α (alpha) may be 45° or less, 30° or less, 20° orless, 15° or less, 12° or less, 10° or less, or 5° or less. At a lowerend, the angle α (alpha) may be, in one or more embodiments, 2° or more,3° or more, 4° or more, or 5° or more.

FIG. 11 depicts one alternative triangular-shaped filter bag that may beused in one or more embodiments of a filter bag assembly and/or airfilter system as described herein. The triangular-shaped bag 240includes a top vertex 245 and a pair of bottom vertices 246 and 247. Apair of side surfaces 242 extend between the top vertex 245 and each ofthe bottom vertices 246 and 247. A bottom surface 244 extends betweenthe bottom vertices 246 and 247. When mounted on a cage in a filter bagassembly as described herein, the cage axis would extend perpendicularlyout of the paper on which FIG. 11 is located.

The bottom surface 244 may be described as having a width wb extendingbetween the bottom vertices 246 and 247. The left side surface 242 maybe described as having a height s1 measured between the top vertex 245and bottom vertex 247. The right side surface 242 may be described ashaving a height s2 measured between the top vertex 245 and bottom vertex246. As discussed herein the width of the bottom surface (wb) ispreferably less than the height of either of the side surfaces (s1 ors2).

The triangular-shaped bag 240 may optionally be described with respectto the angle formed between the side surfaces 242 at vertex 245. Inparticular, the angle α (alpha) formed by side surfaces 242 at vertex245 may be selected such that the width (wb) of the bottom surface 244has a selected relationship with the heights of the side surfaces 242.In one or more embodiments, the angle α (alpha) may be 45° or less, 30°or less, 20° or less, 15° or less, 12° or less, 10° or less, or 5° orless. At a lower end, the angle α (alpha) may be, in one or moreembodiments, 2° or more, 3° or more, 4° or more, or 5° or more.

The depicted triangular-shaped bag 240 forms a triangle that may bedescribed as being an obtuse triangle. The axis 201 depicted in FIG. 11may be described as bisecting the angle α (alpha) and, as a result, theaxis 201 also bisects the bottom surface 244. In one or more embodimentsof triangular-shaped filter bags as described herein, the axis passingthrough the top vertex and bisecting the angle formed at that vertex maypreferably be oriented generally vertically within the dirty air chamberof an air filter system. With respect to the embodiment oftriangular-shaped filter bag 240, axis 201 may be oriented verticallyor, alternatively, the axis 201 may canted or angled with respect to avertical axis

Although the bottom surface 244 of the triangular-shaped filter bag 240may not be oriented transverse to the vertical axis, particulate matterdislodged from the bottom surface 244 during pulse cleaning would have avertical force component that, when added to the force applied bygravity, would preferentially move the dislodged particulate matterdownward as described in connection with other illustrative embodimentsof filter bags described herein.

FIG. 12 depicts a pair of triangular-shaped filter bags 240. Thetriangular-shaped filter bag 240 on the right side of FIG. 12 hasessentially the same shape as the filter bag 240 depicted in FIG. 11.The triangular-shaped filter bag 240 on the left side of FIG. 12 is amirror image of the filter bag 240 on the right side of FIG. 12. Boththe left and right side triangular-shaped filter bags 240 includevertically oriented surfaces 242 facing each other and aligned with avertical axis V, while the outer side surfaces 243 of thetriangular-shaped filter bags 240 face away from each other. Onepotential advantage of such an arrangement is that the triangular-shapedfilter bags 240 may be spaced closer together (in a direction transverseto the vertical axis), thus increasing the surface area of filter mediaavailable within a given dirty air chamber volume while retaining theparticulate loading and pulse cleaning advantages that may be associatedwith triangular-shaped filter bags as described herein.

FIG. 13 depicts one alternative triangular-shaped filter bag that may beused in one or more embodiments of a filter bag assembly and/or airfilter system as described herein. The triangular-shaped bag 340includes a top vertex 345 and a pair of bottom vertices 346 and 347. Apair of side surfaces 342 extend between the top vertex 345 and each ofthe bottom vertices 346 and 347. A bottom surface 344 extends betweenthe bottom vertices 346 and 347. When mounted on a cage in a filter bagassembly as described herein, the cage axis would extend perpendicularlyout of the paper on which FIG. 13 is located.

The bottom surface 344 may be described as having a width wb extendingbetween the bottom vertices 346 and 347. The left side surface 342 maybe described as having a height s1 measured between the top vertex 345and bottom vertex 347. The right side surface 342 may be described ashaving a height s2 measured between the top vertex 345 and bottom vertex346. As discussed herein the width of the bottom surface (wb) ispreferably less than the height of either of the side surfaces (s1 ors2).

The triangular-shaped bag 340 may optionally be described with respectto the angle formed between the side surfaces 342 at vertex 345. Inparticular, the angle α (alpha) formed by side surfaces 342 at vertex345 may be selected such that the width (wb) of the bottom surface 344has a selected relationship with the heights of the side surfaces 242.In one or more embodiments, the angle α (alpha) may be 45° or less, 30°or less, 20° or less, 15° or less, 12° or less, 10° or less, or 5° orless. At a lower end, the angle α (alpha) may be, in one or moreembodiments, 2° or more, 3° or more, 4° or more, or 5° or more.

The depicted triangular-shaped bag 340 forms a triangle that may bedescribed as being a right triangle. The axis 301 depicted in FIG. 13may be described as bisecting the bottom surface 344. In one or moreembodiments of triangular-shaped filter bags as described herein, theaxis passing through the top vertex and bisecting the bottom surface maybe oriented generally vertically within the dirty air chamber of an airfilter system. With respect to the embodiment of triangular-shapedfilter bag 340, axis 301 may be oriented vertically or, alternatively,the right side surface 342 (forming a right angle with the bottomsurface 344) may be oriented vertically such that the bottom surface 344is oriented generally horizontally to a vertical axis. As used herein,the phrase “generally horizontal” (and variations thereof) means thatthe component or components (e.g., a filter bag and/or filter bagassembly with cage) is/are arranged such that the component orcomponents form an angle of 45 degrees or less, 30 degrees or less, 20degrees or less, or 15 degrees or less off of a horizontal line (wheregravitational force vectors define the vertical axis). For example, thecage axis or filter bag axis may define such an angle with a horizontalline if the filter bag and/or cage is canted with respect to perfectlyhorizontal line.

Even if the bottom surface 344 of the triangular-shaped filter bag 340is not oriented transverse to the vertical axis (where, for example, theaxis 301 is oriented vertically), particulate matter dislodged from thebottom surface 344 during pulse cleaning would have a vertical forcecomponent that, when added to the force applied by gravity, wouldpreferentially move the dislodged particulate matter downward asdescribed in connection with other illustrative embodiments of filterbags described herein.

Another illustrative embodiment of a filter bag assembly supported on afilter guide attached to a tubesheet is depicted in a perspective viewin FIG. 14. The depicted filter bag assembly includes a flange assemblythat, in the depicted embodiment, includes a base 432 and a clamp 434,along with a filter bag 440 and a cage 450 attached to the base 132 ofthe flange assembly. A clean-air outlet 436 is formed in the base 432 ofthe flange assembly to allow for passage of air into or out of theinterior volume of the filter bag 440. The cage 450 extends away fromthe flange assembly along a cage axis 451 and is used to support filterbag 440 in a selected shape (e.g., triangular, as depicted).

The filter bag assembly of FIG. 14 also includes a pulse collector 484attached to the base 432 of the flange assembly and configured to passthrough the aperture 426 in tubesheet 420 when the filter bag assemblyis properly positioned for use in a dirty air chamber.

The air filter system depicted in FIG. 14 also includes an alternativeillustrative embodiment of a filter guide used to support the filter bagassembly (i.e., the flange assembly including base 432 and clamp 434,filter bag 440, and cage 450). The depicted embodiment of a filter guideincludes struts 460 that are attached to tubesheet 420 and extend awayfrom tubesheet 420 along cage axis 451. The struts 460 of thisembodiment of a filter guide can be contrasted with the external filterguide 60 seen in, e.g., the illustrative embodiment depicted in FIGS.4A-4G and 6A.

Another optional feature depicted in connection with the illustrativeembodiment of a filter bag assembly and associated air filter systemstructure depicted in FIG. 14 is a cover 470 used to close an accessport 474 in an access panel. The cover 470 includes embossments 476 thatmay, in one or more embodiments, be configured to have a shape that iscomplementary to the shape of the second end 443 of the filter bag 442,as described herein, such embossments may provide advantages such as,for example, additional stability to the filter bag assemblies proximatethe access panel, more uniform force distribution over the second end443 of the filter bag 440 and, therefore, over the cage located withinthe filter bag 440, verification of proper installation of the filterbag assemblies (such that, for example, the bottom surface of thetriangular filter bag is properly oriented in the dirty air chamber),etc.

FIG. 15 is an enlarged partial cross-sectional view of the filter bagassembly of FIG. 14 depicting illustrative embodiments of the junctionsbetween the flange assembly components, filter, and tubesheet. Inparticular, the view of FIG. 15 depicts filter bag 440 supported onfilter cage 450. Filter cage 450 is attached to the base 432 of theflange assembly with the bag opening 441 captured between the clamp 434and base 132 of the flange assembly. The bag opening 441 may include acompressible seal/cuff (similar to that found in, e.g., cuff 649 offilter bag 640 depicted in FIGS. 17-19) that may enhance sealing of thebag opening 441 between the base 432 and the clamp 434 to prevent thepassage of air and/or particulate matter through the interface betweenthe base 432, the clamp 434, and filter bag opening 441. Anotheroptional component depicted in FIG. 15 is a clamp assembly 439 used tosecure clamp 434 on base 432, with opening 441 of filter bag 440 securedtherebetween. Clamp 439 may take any of a suitable number of forms suchas, e.g., a spring clamp assembly similar to those used in connectionwith, e.g., many other filter cartridges and elements.

FIG. 15 also depicts a seal 438 located on the base 432 of the flangeassembly. The seal 438 faces the tubesheet 420 and, when the base 132 ofthe flange assembly is moved into contact with the tubesheet 420, theseal 438 preferably forms a seal between the base 132 and the tubesheet420 that prevents the passage of air and/or particulate matter throughthe interface between the flange assembly and the tubesheet 420 asdescribed in connection with other illustrative embodiments herein.

FIG. 16 is a cross-sectional view of another illustrative embodiment ofa filter bag assembly including an envelope-shaped filter bag 540supported by a cage 550 on a flange assembly 530 as described herein.Although some illustrative embodiments of air filter systems and filterbag assemblies described herein may advantageously use filter bags andcages that result in triangularly shaped filter bags, many of theadvantages and benefits associated with filter bag assemblies that arecompressed within a dirty air chamber as described herein are alsoavailable in connection with filter bags on filter bag assemblies havingany selected shape.

In particular, FIG. 16 depicts one embodiment of a more conventionalenvelope-shaped filter bag assembly in which the opposite major sides ofthe filter bag 540 are generally parallel to each other in use (e.g.,have an angle α (alpha) that is essentially 0° (with reference to FIGS.10-13)). The filter bag 540 is mounted on a cage constructed of struts550 that define the envelope shape of the filter bag 540 mountedthereon.

The struts 550 are attached to a flange assembly 530 that includes aclean air outlet 536 as described in connection with other embodimentsof flange assemblies of filter bag assemblies as described herein. Theclean air outlet 536 is, in the depicted illustrative embodimentelongated along an outlet axis 531 as described in connection with otherillustrative embodiments herein.

The struts 550 of the cage attached to the flange assembly 530 alsoextend away from that flange assembly 530 along a cage axis 551 to adistal end where they support a second end of the filter bag 540 asdescribed in connection with other illustrative embodiments herein. Alsodepicted in FIG. 16 are a portion of the tubesheet 520 against whichflange assembly 530 is forced to provide a seal, along with an aperture526 in the tubesheet 520 through which air passes into or out of theclean air chamber located on the opposite side of the tubesheet 520.

FIGS. 17-19 depict one illustrative embodiment of a triangular filterbag that may be used in one or more embodiments of filter bag assembliesand air filter systems as described herein. The triangular filter bag640 includes an opening 643, a closed end provided by a substantiallytriangular end cap 690, and a body 680 extending from the opening 643 tothe closed end along a bag axis 641 that extends between the opening 643to the closed end of the filter bag 640.

The body 680 of the triangular filter bag 640 is formed of filter mediasuitable for removing particulate matter from air in the application forwhich it is intended. In one or more embodiments, the body 680 mayconsist essentially of filter media with no other components provided.With reference to FIG. 18, the body 680 may include seam edges 682 and683 that are attached to each other to form a longitudinal seam 682/683as seen in, e.g., FIG. 17. When the seam edges 682/683 are attached toeach other, the body may be described as taking a tubular shape thatdefines an interior volume between the opening 643 and the closed anddefined by the triangular end cap 690. In that tubular shape, the filtermedia of the body 680 also defines a closed end edge 684 located at theclosed end of the filter bag 640 and an opening edge 685 located at theopening 643 of the filter bag 640.

In one or more embodiments, the junction between the longitudinal seam682/683 with the triangular end cap 690 may be located along one of theside edges 692 of the triangular end cap 690 between the bottom edge 694and the apex 695 of the triangular end cap. In one or more alternativeembodiments, a junction between a longitudinal seam and a triangular endcap of a filter bag as described herein may be located along the bottomedge 694 or the apex 695. Further, although body 680 includes only onelongitudinal seam 682/683, one or more alternative embodiments oftriangular filter bags as described herein may include two or moreseams.

The triangular end cap of one or more embodiments of triangular filterbags as described herein may, with reference to the illustrativeembodiment of triangular end cap 690, include two side edges 692 thatextend between a bottom edge 694 and an apex 695. Described alternately,the side edges 692 of the triangular end cap 690 may be described asmeeting at the apex 695 at a location distal from the bottom edge 694.

To provide a filter bag capable of removing particulate matter from air,the filter media of the body 680 at the closed end edge 684 is sealed tothe side edges 692, bottom edge 694 and apex 695 of the triangular endcap 690 such that particulate matter is substantially prevented frompassing through those junctions.

The triangular end cap 690 may, in one or more embodiments, define thegenerally triangular-shaped of the filter bag 640 along its length andwill more definitely defined the triangular-shaped of the filter bag 640proximate the triangular end cap 690. With reference to FIG. 19, theshape of the triangular end cap 690 can be described with reference tothe included angle formed between the side edges 692 of the triangularend cap 690. In particular, the bottom edge 694, apex 695, and sideedges 692 of the triangular end cap 690 may, in one or more embodiments,be described as defining an included angle α (alpha) between the sideedges 692 at the apex 695 of 20° or less, 15° or less, 12° or less, 10°or less, or 5° or less. At a lower end, the angle α (alpha) may be, inone or more embodiments, 2° or more, 3° or more, 4° or more, or 5° ormore.

The triangular end caps that may be used in one or more embodiments oftriangular filter bags as described herein may alternatively bedescribed with respect to the dimensions of the features of thetriangular end cap. For example, the triangular end cap 690, whenprojected onto a flat surface along the bag axis 641 may, in one or moreembodiments, define a height (h) between the apex 695 and the bottomedge 694. The projection of triangular end cap 690 may also define awidth (w) across the bottom edge 694 between the side edges 692. In oneor more embodiments of triangular filter bags as described herein, theheight (h) is greater than the width (w). More particularly, in one ormore embodiments, the height (h) defined between the bottom edge and theapex of a triangular end cap may be 4 or more, 6 or more, 8 or more, 10or more, 12 or more, or 15 times or more the width (w) defined along thebottom edge between the sides of the triangular end. In one or moreembodiments, the height (h) defined between the bottom edge and the apexof a triangular end cap may be, at an upper end, 20 or less, 15 or less,12 or less, 10 or less, 8 or less, or 6 or less times the width (w)defined along the bottom edge between the sides of the triangular end.In one embodiment, the height (h) defined between the bottom edge andthe apex of a triangular end cap may be 7 to 8 times the width (w)defined along the bottom edge between the sides of the triangular end.It should be noted that the height (h) is preferably measured along anend cap axis 691 that extends between the bottom edge 694 and the apex695 and may, in one or more embodiments, be described as bisecting boththe bottom edge 694 and the apex 695 and/or defining an axis of symmetryof the triangular end 690. In one or more embodiments of filter bagsincluding triangular end caps as described herein, the triangular endmay be constructed of filter media, e.g., the same filter media used forthe body 680 of the filter bag. In one or more alternative embodiments,the triangular end caps may be constructed of materials that areimpermeable to air (unlike the filter media used for the body 680). Inone or more embodiments, the triangular end caps may be substantiallyrigid, self-supporting articles, while in other embodiments the triangleare end caps may be constructed of flexible materials that are notcapable of self-support.

In one or more embodiments of filter bags including triangular end capsas described herein, the closed end edge 684 of the body 680 may besealed to the side edges 692 of the triangular end cap 690 using anysuitable technique or combination of techniques sufficient to providestructural integrity to that junction as well as limit/prevent passageof particulate matter through that junction. In one or more embodiments,the closed end edge may be sealed to the side edges using one or more ofa sewn seam, a stitched seam, an adhesive seam, a chemically weldedseam, and a thermally welded seam.

In one or more embodiments of filter bags including triangular end capsas described herein, the closed end edge 684 of the body 680 may besealed to the bottom edge 694 of the triangular end cap 690 using anysuitable technique or combination of techniques sufficient to providestructural integrity to that junction as well as limit/prevent passageof particulate matter through that junction. In one or more embodiments,the closed end edge may be sealed to the side edges using one or more ofa sewn seam, a stitched seam, an adhesive seam, a chemically weldedseam, and a thermally welded seam.

In one or more embodiments of filter bags including triangular end capsas described herein, the closed end edge 684 of the body 680 may besealed to the apex 695 of the triangular end cap 690 using any suitabletechnique or combination of techniques sufficient to provide structuralintegrity to that junction as well as limit/prevent passage ofparticulate matter through that junction. In one or more embodiments,the closed end edge may be sealed to the side edges using one or more ofa sewn seam, a stitched seam, an adhesive seam, a chemically weldedseam, and a thermally welded seam.

With reference to FIG. 19, filter bag 640 also includes an optional cuff649 attached to the filter media of the body 680 along the opening edge685 of the body 680. The cuff 649 may, in one or more embodiments, beused to enhance sealing of the bag opening 643 to a flange assembly of afilter bag assembly as described herein. In one or more embodiments, thecuff 649 may be thicker than the filter media. In one or moreembodiments, the cuff 649 may include one or more resilient,compressible materials or bodies (see, e.g., body 648 in FIG. 18)suitable to enhance a seal formed between the bag opening 643 and aflange assembly of a filter bag assembly as described herein.

Following are some illustrative embodiments of the air filter systems,filter bag assemblies, and filter bags described herein.

Embodiment A1 is an air filter system comprising: a tubesheet separatinga housing into a dirty air chamber and a clean air chamber, wherein thetubesheet comprises an aperture placing the dirty air chamber in fluidcommunication with the clean air chamber, and wherein the housingcomprises an access panel located across the dirty air chamber from thetubesheet; a filter bag assembly located in the dirty air chamber, thefilter bag assembly comprising: a flange assembly comprising an interiorface and a tubesheet face facing the tubesheet, the flange assemblysurrounding the aperture in the tubesheet and comprising a clean airoutlet extending through the flange assembly, the clean air outlet influid communication with the aperture in the tubesheet; a cagecomprising a first cage end attached to the flange assembly andextending over a cage length to a second cage end distal from the flangeassembly, the cage defining a cage axis extending between the first cageend and the second cage end, the cage further comprising a plurality ofstruts extending away from the interior face of the flange assemblytowards the second cage end; and a filter bag comprising filter mediadefining an interior volume of the filter bag, wherein the filter bagextends from a first end to a second end, wherein a portion of thefilter media defines a bag opening at the first end of the filter bag;wherein the bag opening is attached to flange assembly, wherein the bagopening and the flange assembly form a seal around the clean air outletsuch that air entering the interior volume of the filter bag must passthrough the filter media of the filter bag or through the clean airoutlet of the flange assembly; a filter access port in the access panelof the housing, the filter access port comprising a cover movablebetween a closed position and an open position, wherein the cover closesthe filter access port when the cover is in the closed position andwherein the filter bag assembly can be inserted into or removed from thedirty air chamber through the filter access port when the cover is inthe open position; a seal located around the aperture in the tubesheetbetween the tubesheet face of the flange assembly and the tubesheet suchthat air passing through the aperture in the tubesheet must pass throughthe clean air outlet in the flange assembly before entering or leavingthe interior volume of the filter bag; a seal actuator proximate thefilter access port in the access panel, the seal actuator configured toapply a seal force on the second cage end through the second end of thefilter bag, wherein the seal force is directed along the cage axis andis transferred to the seal through the cage and the flange assembly; anda pulse generator located in the clean air chamber and configured todeliver pulses of air into the interior volume of the filter bag throughthe aperture in the tubesheet and the clean air outlet of the flangeassembly, the pulses of air passing through the aperture and the cleanair outlet before reaching the interior volume of the filter bag.

Embodiment A2 is a version of Embodiment A1 in which the seal actuatorcomprises the cover of the filter access port, wherein, when the filterbag assembly is located in mounted on the filter guide in the dirty airchamber and the cover is in the closed position, the cover applies theseal force on the second cage end.

Embodiment A3 is a version of any one of Embodiments A1 or A2, whereinthe flange assembly comprises a base comprising the tubesheet face ofthe flange assembly and a clamp configured to attach to the base on theinterior face of the flange assembly, wherein the clean air outletextends through the base and the clamp, and wherein the bag opening ofthe filter bag is retained between the clamp and the base on theinterior face of the flange assembly.

Embodiment A4 is a version of Embodiment A3, wherein the bag opening,the clamp, and the base form the seal around the clean air outlet suchthat air entering the interior volume of the filter bag must passthrough the filter media of the filter bag or through the clean airoutlet of the flange assembly.

Embodiment A5 is a version of any one of Embodiments A1 to A4, whereinthe system comprises a filter guide in the dirty air chamber, the filterguide extending along a guide axis passing through the tubesheet and theaccess panel, wherein the guide axis is aligned with the bag axis, andwherein the filter bag assembly is mounted on the filter guide, and,optionally, wherein the filter guide extends from the tubesheet to theaccess panel of the housing. Embodiment A6 is a version of EmbodimentA5, wherein the flange assembly comprises a guide aperture, and whereinthe filter guide passes through the guide aperture.

Embodiment A7 is a version of any one of Embodiments A1 to A6, whereinthe system comprises a bag support configured to support the second endof the filter bag. Embodiment A8 is a version of Embodiment A7, whereinthe bag support comprises a bag support connector attached to the filterbag proximate the second end of the filter bag, and a chamber connectorpositioned in the dirty air chamber proximate the access panel of thehousing, wherein the bag support connector and the chamber connector areconfigured to interlock with each other to support the second end of thefilter bag in the dirty air chamber, and, optionally, wherein the bagsupport connector comprises at least one of a hook and a loop.Embodiment A9 is a version of Embodiment A8, wherein the chamberconnector is attached to the filter guide.

Embodiment A10 is a version of any one of Embodiments A1 to A9, wherein,in each cross-section taken in a plane transverse to the cage axis overa majority of the cage length, the plurality of struts define a trianglecomprising a top vertex and a pair of bottom vertices opposite the topvertex, and wherein, when the cage is located in the filter bag, thefilter media of the filter bag defines a pair of side surfaces and abottom surface, wherein each side surface of the pair of side surfacescomprises a top edge proximate the top vertex of each triangle definedby the plurality of struts, and wherein each side surface of the pair ofside surfaces comprises a bottom edge distal from the top edge, whereinthe bottom edges of the side surfaces are proximate the bottom verticesof each triangle defined by the plurality of struts, and wherein thebottom surface of the filter media extends between the bottom edges ofthe side surfaces; and, optionally, wherein the top angle formed at thetop vertex by the bottom vertices opposite the top vertex is 20° orless, 15° or less, 12° or less, 10° or less, or 5° or less; and,optionally, the top angle formed at the top vertex by the bottomvertices opposite the top vertex is 2° or more, 3° or more, 4° or more,or 5° or more.

Embodiment A11 it is a version of any one of Embodiments A1 to A10,wherein the bottom surface of the filter media comprises a widthmeasured between the bottom edges of the side surfaces of the filtermedia in a direction transverse to the cage axis, and wherein each sidesurface comprises a height measured between the top edge and the bottomedge transverse to the cage axis, wherein the width of the bottomsurface is 50% or less, 40% or less, 30% or less, 20% or less, 15% orless, 12% or less, 10% or less, 8% or less, or 5% or less of the heightof either side surface of the pair of side surfaces and, optionally,wherein the width of the bottom surface is 4% or more, 5% or more, 6% ormore, 8% or more, 10% or more, 12% or more, 15% or more of the height ofeither side surface of the pair of side surfaces.

Embodiment A12 is a version of any one of Embodiments A10 to A11,wherein the clean air outlet comprises an elongated shape extending froma top end to a bottom end, wherein an outlet axis extends between thetop end and the bottom end of the clean air outlet, and wherein aprojection of the outlet axis along the cage axis passes between thepair of bottom vertices of each triangle defined by the plurality ofstruts.

Embodiment A13 is a version of any one of Embodiments A10 to A12,wherein the plurality of struts comprises a top strut and a pair ofbottom struts, wherein the top strut defines the top vertex of eachtriangle defined by the plurality of struts, and wherein the bottomstruts define the bottom vertices of each triangle defined by theplurality of struts, and optionally, wherein a junction between the topstrut and the flange assembly and junctions between each of the bottomstruts and the flange assembly define a triangle on the flange assembly,and wherein the clean air outlet is located within the triangle definedby the junctions between the top strut and the bottom struts and theflange assembly.

Embodiment A14 is a version of any one of Embodiments A10 to A13,wherein each triangle defined by the plurality of struts comprises anacute, optionally isosceles, triangle.

Embodiment A15 is a version of any one of Embodiments A10 to A14,wherein the top vertex of each triangle defined by the plurality ofstruts is located between the filter guide and the bottom vertices ofeach triangle defined by the plurality of struts.

Embodiment A16 is a version of any one of Embodiments A1 to A15, whereinthe pulse generator comprises a plurality of ports facing the aperturein the tubesheet, wherein air in the pulses of air passes through theplurality of ports.

Embodiment A17 is a version of any one of Embodiments A1 to A16, whereinthe cage axis is oriented generally horizontally within the dirty airchamber, and wherein the housing comprises a hopper located below thefilter bag assembly, wherein particulate matter dislodged from thefilter media is urged towards the hopper under the force of gravity.

Embodiment A18 is a version of any one of Embodiments A1 to A17, whereinthe filter guide is located outside of the interior volume of the filterbag.

Embodiment A19 is a version of any one of Embodiments A1 to A17, whereinthe filter guide is located within the interior volume of the filterbag.

Embodiment B is use of an air filter system according to any one ofEmbodiments A1 to A19 to remove particulate matter from dirty air usingthe filter bag of the filter bag assembly.

Embodiment C21 is a filter bag assembly comprising: a flange assemblycomprising an interior face and a tubesheet face, the flange assemblycomprising a clean air outlet extending through the flange assembly,wherein the clean air outlet extends from a top end to a bottom end,wherein an outlet axis extends between the top end and the bottom end ofthe clean air outlet; a cage comprising a first cage end attached to theflange assembly and extending over a cage length to a second cage enddistal from the flange assembly, the cage defining a cage axis extendingbetween the first cage end and the second cage end, the cage furthercomprising a plurality of struts extending away from the interior faceof the flange assembly towards the second cage end, wherein, in eachcross-section taken in a plane transverse to the cage axis over amajority of the cage length, the plurality of struts define a trianglecomprising a top vertex and a pair of bottom vertices opposite the topvertex; and a filter bag comprising filter media defining an interiorvolume of the filter bag, wherein the filter bag extends from a firstend to a second end, wherein a portion of the filter media defines a bagopening at the first end of the filter bag; wherein the bag opening isattached to the flange assembly, wherein the bag opening and the flangeassembly form a seal around the clean air outlet such that air enteringthe interior volume of the filter bag must pass through the filter mediaof the filter bag or through the clean air outlet of the flangeassembly; wherein, when the cage is located in the filter bag, thefilter media of the filter bag defines a pair of side surfaces and abottom surface, wherein each side surface of the pair of side surfacescomprises a top edge proximate the top vertex of each triangle definedby the plurality of struts, and wherein each side surface of the pair ofside surfaces comprises a bottom edge distal from the top edge, whereinthe bottom edges of the side surfaces are proximate the bottom verticesof each triangle defined by the plurality of struts, and wherein thebottom surface of the filter media extends between the bottom edges ofthe side surfaces.

Embodiment C22 is a version of Embodiment C21, wherein the bottomsurface of the filter media comprises a width measured between thebottom edges of the side surfaces of the filter media in a directiontransverse to the cage axis that is less than a height, measured betweenthe top edge and the bottom edge transverse to the cage axis, of eitherside surface of the pair of side surfaces of filter media, and,optionally, wherein the width of the bottom surface is 50% or less, 40%or less, 30% or less, 20% or less, 15% or less, 12% or less, 10% orless, 8% or less, or 5% or less of the height of either side surface ofthe pair of side surfaces, and, optionally, wherein the width of thebottom surface may be 4% or more, 5% or more, 6% or more, 8% or more,10% or more, 12% or more, 15% or more of the height of either sidesurface of the pair of side surfaces.

Embodiment C23 is a version of any one of Embodiments C21 to C22,wherein an angle formed between the side surfaces at the top edge ofeach triangle defined by the plurality of struts is 45° or less, 30° orless, 20° or less, 15° or less, 12° or less, 10° or less, or 5° or less,and, optionally, the angle formed between the side surfaces at the topedge of each triangle defined by the plurality of struts is 2° or more,3° or more, 4° or more, or 5° or more.

Embodiment C24 is a version of any one of Embodiments C21 to C23,wherein a projection of the outlet axis along the cage axis passesbetween the pair of bottom vertices of each triangle defined by theplurality of struts, and, optionally, wherein the projection of theoutlet axis passes through the top vertex of each triangle defined bythe plurality of struts.

Embodiment C25 is a version of any one of Embodiments C21 to C24,wherein the filter media of the filter bag comprises a continuous hoopof filter media, the continuous hoop of filter media extends from thebag opening to the second edge of the filter bag and wherein the filterbag comprises a seam located along the second end of the filter bag,wherein the seam closes the continuous hoop of filter media at thesecond end of the filter bag.

Embodiment C26 it is a version of any one of Embodiments C21 to C25,wherein the plurality of struts comprises a top strut and a pair ofbottom struts, wherein the top strut defines the top vertex of eachtriangle defined by the plurality of struts, and wherein the bottomstruts define the bottom vertices of each triangle defined by theplurality of struts, and, optionally, wherein a junction between the topstrut and the flange assembly and junctions between each of the bottomstruts and the flange assembly define a triangle on the flange assembly,and wherein the clean air outlet is located within the triangle definedby the junctions between the top strut and the bottom struts and theflange assembly.

Embodiment C27 is a version of any one of Embodiments C21 to C26,wherein each triangle defined by the plurality of struts comprises anacute, optionally isosceles, triangle.

Embodiment C28 is a version of any one of Embodiments C21 to C27,wherein the flange assembly comprises a base comprising the tubesheetface of the flange assembly and a clamp configured to attach to the baseon the interior face of the flange assembly, wherein the clean airoutlet extends through the base and the clamp, and wherein the bagopening of the filter bag is retained between the clamp and the base onthe interior face of the flange assembly, and optionally, wherein thebag opening, the clamp, and the base form the seal around the clean airoutlet such that air entering the interior volume of the filter bag mustpass through the filter media of the filter bag or through the clean airoutlet of the flange assembly.

Embodiment C29 is a version of any one of Embodiments C21 to C28,wherein the flange assembly comprises a guide aperture and, optionally,wherein the guide aperture is located above the cage and the top edgesof the side surfaces formed by the filter media of the filter bag.

Embodiment C30 is a version of any one of Embodiments C21 to C29,wherein the filter bag comprises a bag support connector attached to thefilter bag proximate the second end of the filter bag, the bag supportlocated outside of the interior volume of the filter bag, and,optionally, wherein the bag support comprises at least one of a loop anda hook. Embodiment C31 is a version of Embodiment 30, wherein the bagsupport is attached to the filter bag proximate the top edges of theside surfaces of the filter media of the filter bag.

Embodiment C32 is a version of any one of Embodiments C21 to C31,wherein the filter bag assembly further comprises a pulse collectorextending away from the tubesheet face of the flange assembly, the pulsecollector surrounding the clean air outlet and configured to collect andpass air approaching the clean air outlet from the tubesheet face of theflange assembly through the clean air outlet.

Embodiment C33 is a version of any one of Embodiments C21 to C32,wherein the flange assembly comprises a sealing surface surrounding theclean air outlet on the tubesheet face of the flange assembly.

Embodiment D includes use of a filter bag assembly according to any oneof Embodiments C21 to C33 to remove particulate matter from dirty airusing the filter bag.

Embodiment E35 is an air filter system comprising: a tubesheetseparating a housing into a dirty air chamber and a clean air chamber,wherein the tubesheet comprises an aperture placing the dirty airchamber in fluid communication with the clean air chamber, and whereinthe housing comprises an access panel located across the dirty airchamber from the tubesheet; a filter guide in the dirty air chamber, thefilter guide extending along a guide axis passing through the tubesheetand the access panel. The system includes a filter bag assembly mountedon the filter guide and located in the dirty air chamber, the filter bagassembly comprising: a flange assembly comprising an interior face and atubesheet face facing the tubesheet, the flange assembly surrounding theaperture in the tubesheet and comprising a clean air outlet extendingthrough the flange assembly, the clean air outlet in fluid communicationwith the aperture in the tubesheet, wherein the clean air outletcomprises an elongated shape extending from a top end to a bottom end,wherein an outlet axis extends between the top end and the bottom end ofthe clean air outlet; a cage comprising a first cage end attached to theflange assembly and extending over a cage length to a second cage enddistal from the flange assembly, the cage defining a cage axis extendingbetween the first cage end and the second cage end, the cage furthercomprising a plurality of struts extending away from the interior faceof the flange assembly towards the second cage end, wherein, in eachcross-section taken in a plane transverse to the cage axis over amajority of the cage length, the plurality of struts define a trianglecomprising a top vertex and a pair of bottom vertices opposite the topvertex; and a filter bag comprising filter media defining an interiorvolume of the filter bag, wherein the filter bag extends from a firstend to a second end, wherein a portion of the filter media defines a bagopening at the first end of the filter bag; wherein the bag opening isattached to flange assembly, wherein the bag opening and the flangeassembly form a seal around the clean air outlet such that air enteringthe interior volume of the filter bag must pass through the filter mediaof the filter bag or through the clean air outlet of the flangeassembly; wherein, when the cage is located in the filter bag, thefilter media of the filter bag defines a pair of side surfaces and abottom surface, wherein each side surface of the pair of side surfacescomprises a top edge proximate the top vertex of each triangle definedby the plurality of struts, and wherein each side surface of the pair ofside surfaces comprises a bottom edge distal from the top edge, whereinthe bottom edges of the side surfaces are proximate the bottom verticesof each triangle defined by the plurality of struts, and wherein thebottom surface of the filter media extends between the bottom edges ofthe side surfaces; a filter access port in the access panel of thehousing, the filter access port comprising a cover movable between aclosed position and an open position, wherein the cover closes thefilter access port when the cover is in the closed position and whereinthe filter bag assembly can be inserted into or removed from the dirtyair chamber when the cover is in the open position, wherein, optionally,the cover acts on and forces the tubesheet face of the flange assemblyagainst the tubesheet when the filter bag assembly is mounted on thefilter guide and the cover is in the closed position; and a pulsegenerator located in the clean air chamber and configured to deliverpulses of air into the interior volume of the filter bag through theaperture in the tubesheet and the clean air outlet of the flangeassembly, the pulses of air passing through the aperture and the cleanair outlet before reaching the interior volume of the filter bag.

Embodiment E36 is a version of Embodiment E35, wherein the bottomsurface of the filter media comprises a width measured between thebottom edges of the side surfaces of the filter media in a directiontransverse to the cage axis that is less than a height, measured betweenthe top edge and the bottom edge transverse to the cage axis, of eitherside surface of the pair of side surfaces of filter media, and,optionally, wherein width of the bottom surface is 50% or less, 40% orless, 30% or less, 20% or less, 15% or less, 12% or less, 10% or less,8% or less, or 5% or less of the height of either side surface of thepair of side surfaces, and, optionally, wherein the width of the bottomsurface may be 4% or more, 5% or more, 6% or more, 8% or more, 10% ormore, 12% or more, 15% or more of the height of either side surface ofthe pair of side surfaces.

Embodiment E37 is a version of any one of Embodiments E35 to E36,wherein an angle formed between the side surfaces at the top edge ofeach triangle defined by the plurality of struts is 45° or less, 30° orless, 20° or less, 15° or less, 12° or less, 10° or less, or 5° or less,and, optionally, the angle formed between the side surfaces at the topedge of each triangle defined by the plurality of struts is 2° or more,3° or more, 4° or more, or 5° or more.

Embodiment E38 is a version of any one of Embodiments E35 to E37,wherein a projection of the outlet axis along the cage axis passesbetween the pair of bottom vertices of each triangle defined by theplurality of struts, and optionally, wherein the projection of theoutlet axis passes through the top vertex of each triangle defined bythe plurality of struts.

Embodiment E39 is a version of any one of Embodiments E35 to E38,wherein the filter media of the filter bag comprises a continuous hoopof filter media, the continuous hoop of filter media extends from thebag opening to the second edge of the filter bag, and wherein the coveracts on the second cage end to force the flange assembly against thetubesheet when the filter bag assembly is mounted on the filter guideand the cover is in the closed position.

Embodiment E40 is a version of any one of Embodiments E35 to E39,wherein the plurality of struts comprises a top strut and a pair ofbottom struts, wherein the top strut defines the top vertex of eachtriangle defined by the plurality of struts, and wherein the bottomstruts define the bottom vertices of each triangle defined by theplurality of struts, and, optionally, wherein a junction between the topstrut and the flange assembly and junctions between each of the bottomstruts and the flange assembly define a triangle on the flange assembly,and wherein the clean air outlet is located within the triangle definedby the junctions between the top strut and the bottom struts and theflange assembly.

Embodiment E41 is a version of any one of Embodiments E35 to E40,wherein each triangle defined by the plurality of struts comprises anacute, optionally isosceles, triangle.

Embodiment E42 is a version of any one of Embodiments E35 to E41,wherein the flange assembly comprises a base comprising the tubesheetface of the flange assembly and a clamp configured to attach to the baseon the interior face of the flange assembly, wherein the clean airoutlet extends through the base and the clamp, and wherein the bagopening of the filter bag is retained between the clamp and the base onthe interior face of the flange assembly, and, optionally, wherein thebag opening, the clamp, and the base form the seal around the clean airoutlet such that air entering the interior volume of the filter bag mustpass through the filter media of the filter bag or through the clean airoutlet of the flange assembly.

Embodiment E43 is a version of any one of Embodiments E35 to E42,wherein the flange assembly comprises a guide aperture, and wherein thefilter guide passes through the guide aperture and, optionally, whereinthe guide aperture is located above the cage and the top edges of theside surfaces formed by the filter media of the filter bag.

Embodiment E44 is a version of any one of Embodiments E35 to E43,wherein the filter guide extends from the tubesheet to the access panelof the housing.

Embodiment E45 is a version of any one of Embodiments E35 to E44,wherein the system comprises a bag support configured to support thesecond end of the filter bag. Embodiment E46 is a version of EmbodimentE45, wherein the bag support comprises a bag support connector attachedto the filter bag proximate the second end of the filter bag, and achamber connector positioned in the dirty air chamber proximate theaccess panel of the housing, wherein the bag support connector and thechamber connector are configured to interlock with each other to supportthe second end of the filter bag in the dirty air chamber, and,optionally, wherein the bag support connector comprises at least one ofa hook and a loop. Embodiment E47 is a version of Embodiment E46,wherein the chamber connector is attached to the filter guide.

Embodiment E48 is a version of any one of Embodiments E35 to E47,wherein a flange assembly seal is located between the tubesheet face ofthe flange assembly and the tubesheet.

Embodiment E49 is a version of any one of Embodiments E35 to E48,wherein the pulse generator comprises a plurality of ports facing theaperture in the tubesheet, wherein air in the pulses of air passesthrough the plurality of ports, and, optionally, wherein the pluralityof ports are arranged along a port axis aligned with the outlet axis.Embodiment E50 is a version of Embodiment E49, wherein the port closestto the bottom end of the clean air outlet is larger than the portclosest to the top end of the clean air outlet.

Embodiment E51 is a version of any one of Embodiments E35 to E50,wherein the cage axis is oriented generally horizontally within thedirty air chamber such that the bottom surface of the filter media facesdownward. Embodiment E52 is a version of Embodiment E51, wherein thehousing comprises a hopper located below the filter bag assemblies,wherein particulate matter dislodged from the filter media is urgedtowards the hopper under the force of gravity, and wherein particulatematter on the bottom surface of the filter media is dislodged directlyinto the hopper.

Embodiment F includes use of an air filter system according to any oneof Embodiments E35 to E52 to remove particulate matter from dirty airusing the filter bag of the filter bag assembly.

Embodiment G54 is an air filter system comprising: a tubesheetseparating a housing into a dirty air chamber and a clean air chamber,wherein the tubesheet comprises an aperture placing the dirty airchamber in fluid communication with the clean air chamber, and whereinthe housing comprises an access panel located across the dirty airchamber from the tubesheet; a filter bag assembly located in the dirtyair chamber, the filter bag assembly comprising a flange assemblycovering the aperture in the tube sheet, a cage comprising a first endattached to the flange assembly, the cage extending away from the flangeassembly to a second end proximate the access panel, and a filter bagcomprising a bag opening sealed within the flange assembly, wherein thecage is located in an interior volume of the filter bag with the secondend of the cage proximate a closed end of the filter bag; an access portin the access panel proximate the second end of the cage, wherein thefilter bag assembly passes through the access port during placement inand removal from the dirty air chamber; and means for forcing the flangeassembly against the tubesheet by applying a compression force on thesecond end of the cage, wherein the compression force acts on the secondend of the cage through the filter bag.

Embodiment G55 is a version of Embodiment G54, wherein a seal is locatedaround the aperture in the tubesheet between the flange assembly and thetubesheet such that air passing through the aperture in the tubesheetmust pass through a clean air outlet in the flange assembly beforeentering or leaving the interior volume of the filter bag.

Embodiment G56 is a version of any one of Embodiments G54 to G55,wherein the means for forcing the flange against the tubesheet comprisesa cover closing the access port, wherein the cover applies thecompression force on the second end of the cage through the filter bagwhen the cover closes the access port.

Embodiment G57 is a version of any one of Embodiments G54 to G56, thesystem comprising a filter guide in the dirty air chamber, wherein theflange assembly is supported on the filter guide when moving towards andaway from the tubesheet.

Embodiment G58 is a version of Embodiment G57, wherein the filter guideextends generally horizontally across the dirty air chamber and whereinthe system comprises a filter bag assembly support located outside ofthe interior volume of the filter bag, the filter bag support configuredto support the filter bag assembly proximate the closed end of thefilter bag.

Embodiment G59 is a version of any one of Embodiments G57 to G58,wherein the filter guide is located outside of the interior volume ofthe filter bag. Embodiment G60 is a version of Embodiment G57, whereinthe filter guide is located within the interior volume of the filterbag.

Embodiment G61 is a version of any one of Embodiments G54 to G60,wherein the system comprises means for supporting the closed end of thefilter bag. Embodiment G62 is a version of Embodiment G61, wherein themeans for supporting the closed end of the filter bag comprises a bagsupport connector attached to the filter bag and a chamber connectorpositioned in the dirty air chamber proximate the access panel, whereinthe bag support connector and the chamber connector are configured tointerlock with each other to support the filter bag in the dirty airchamber, and, optionally, wherein the bag support connector comprises atleast one of a hook and a loop. Embodiment G63 is a version ofEmbodiment G62, wherein the chamber connector is attached to the filterguide.

Embodiment G64 is a version of any one of Embodiments G54 to G63,wherein the filter bag assembly defines a cage axis extending away fromthe flange assembly and through the second end of the cage, and wherein,in each cross-section taken in a plane transverse to a cage axis over amajority of the cage, the cage forces the filter bag into asubstantially triangular shape, and optionally, wherein thesubstantially triangular shapes of the filter bag each comprise a pairof side surfaces meeting proximate a top vertex and a bottom surfacespanning between the side surfaces, and, optionally, wherein a top angleformed at the top vertex by the side surfaces is 20° or less, 15° orless, 12° or less, 10° or less, or 5° or less, and, optionally, the topangle is 2° or more, 3° or more, 4° or more, or 5° or more.

Embodiment H65 is use of a system according to any one of EmbodimentsG54 to G64 to remove particulate matter from dirty air using the filterbag of the filter bag assembly.

Embodiment I66 is a method of sealing a filter bag over an aperture in atubesheet of an air filter system, the method comprising: positioning afilter bag assembly in a dirty air chamber of an air filter system witha flange assembly of the filter bag assembly located proximate thetubesheet, wherein a bag opening of a filter bag of the filter bagassembly is located over the aperture in the tubesheet, and wherein theflange assembly covers the aperture; and forcing the flange assemblyagainst the tubesheet by applying a compression force on a cage locatedin an interior volume of the filter bag, wherein the cage is attached tothe flange assembly and extends away from the flange assembly towards aclosed end of the filter bag; wherein air passing through the aperturein the tubesheet from the dirty air chamber must pass through the filterbag before reaching the aperture.

Embodiment I67 it is a version of Embodiment I66, wherein thecompression force is applied on the cage through the filter bag.

Embodiment I68 is a version of any one of Embodiments 166 to 167,wherein the compression force is applied by closing an access port intothe dirty air chamber, wherein the access port is located across thedirty air chamber from the tubesheet.

Embodiment I69 is a version of any one of Embodiments 166 to 168,wherein the positioning the filter bag assembly in the dirty air chambercomprises passing the filter bag assembly into the dirty air chamberthrough the access port. Embodiment I70 is a version of Embodiment I69,wherein the filter bag is attached to the flange assembly before thefilter bag assembly is passed into the dirty air chamber through theaccess port.

Embodiment J71 is use of a triangular filter bag in an air filter systemcomprising an array of two or more of the triangular filter bagsarranged generally horizontally within a dirty air chamber, wherein abottom surface of each triangular filter bag is oriented in a generallyhorizontal position.

Embodiment J72 is a version of Embodiment J71, wherein each triangularbag comprises two side surfaces extending away from the bottom surface,the two side surfaces oriented in a generally vertical position.

Embodiment J73 is a version of any one of Embodiments J71 to J72,wherein the two side surfaces of each triangular filter bag meet abovethe bottom surface, and wherein, optionally, the two side surfacesdefine an included angle between them of 20° or less, 15° or less, 12°or less, 10° or less, or 5° or less, and, optionally, the included angleis 2° or more, 3° or more, 4° or more, or 5° or more.

Embodiment J74 is a version of any one of Embodiments J71 to J73,wherein each triangular bag contains a generally horizontally extendingcage in an interior volume, the cage extending from a bag opening to aclosed end of the bag, wherein the cage optionally comprises atriangular shape. Embodiment J75 is a version of Embodiment J74, whereinthe bag opening is sealed over an aperture in a tubesheet at least inpart by a compression force acting on the closed end of the bag and thecage in a direction towards the open end of the filter bag. EmbodimentJ76 is a version of embodiment J75, wherein the compression force actingon each of the triangular filter bags is provided by a cover closing anaccess opening into the dirty chamber, the cover acting on the closedend of the bag and the cage. Embodiment J77 as a version of embodimentJ76, wherein, for each of the triangular filter bags, the cover closingthe access opening into the dirty chamber comprises a triangularembossment having a shape that is complementary to the triangular shapeof the triangular filter bag at the closed end of the filter bag and/ora triangular shape of the cage located in the interior volume of thetriangular bag. Embodiment J78 is a version of either one of embodimentsJ76 or J77, wherein, for each of the triangular filter bags, the coverclosing the access opening into the dirty chamber comprises a triangularembossment having a shape that is complementary to a triangular shape ofthe cage located in the interior volume of the triangular bag.

Embodiment J79 is a version of any one of Embodiments J71 to J79,wherein each triangular filter bag is removed from the dirty air chamberby withdrawing the triangular filter bag from the dirty air chamber in agenerally horizontal direction.

Embodiment K80 is a triangular filter bag comprising an opening, aclosed end, a body extending from the opening to the closed end along abag axis extending between the opening to the closed end, and asubstantially triangular end cap attached to the body at the closed end;wherein the body comprises filter media taking a tubular shape thatdefines an interior volume between the opening and the closed end,wherein the filter media comprises a closed end edge at the closed endof the bag and an opening edge at the opening of the bag; wherein thetriangular end cap comprises a bottom edge and two side edges extendingaway from the bottom edge, wherein the side edges meet at an apex of thetriangular end cap that is distal from the bottom edge; and wherein thefilter media at the closed end edge of the body is sealed to the bottomedge, the apex, and the two side edges of the triangular end cap.

Embodiment K81 is a version of embodiment K80, wherein the bottom edge,apex, and two side edges of the triangular end cap define an includedangle between the side edges at the apex of 20° or less, 15° or less,12° or less, 10° or less, or 5° or less, and, optionally, the includedangle is 2° or more, 3° or more, 4° or more, or 5° or more.

Embodiment K82 is a version of any one of Embodiments K80 to K81,wherein the triangular end cap, when projected onto a flat surface alongthe bag axis, defines a height between the apex and the bottom edge andalso defines a width across the bottom edge between the side edges,wherein the height is 4 or more, 6 or more, 8 or more, 10 or more, 12 ormore, or 15 or more times the width, and, optionally, wherein the heightis 20 or less, 15 or less, 12 or less, 10 or less, 8 or less, or 6 orless times the width.

Embodiment K83 is a version of any one of Embodiments K80 to K81,wherein the triangular end cap, when projected onto a flat surface alongthe bag axis, defines a height between the apex and the bottom edge andalso defines a width across the bottom edge between the side edges,wherein the height is 7 to 8 times the width.

Embodiment K84 is a version of any one of Embodiments K80 to K83,wherein the triangular end cap comprises filter media. Embodiment K85 isa version of any one of Embodiments K80 to K83, wherein the triangularend cap is impermeable to air.

Embodiment K86 is a version of any one of Embodiments K80 to K85,wherein the body comprises a longitudinal seam extending from the closedend edge to the open edge. Embodiment K87 is a version of embodimentK86, wherein a junction of the longitudinal seam with the triangular endcap is located along one of the side edges of the triangular end capbetween the bottom edge and the apex of the triangular end cap.

Embodiment K88 is a version of any one of Embodiments K80 to K87,wherein the closed end edge is sealed to the side edges of thetriangular end cap using one or more of: a sewn seam, a stitched seam,an adhesive seam, a chemically welded seam, and a thermally welded seam.

Embodiment K89 is a version of any one of Embodiments K80 to K88,wherein the closed end edge is sealed to the bottom edge of thetriangular end cap using one or more of: a sewn seam, a stitched seam,an adhesive seam, a chemically welded seam, and a thermally welded seam.

Embodiment K90 is a version of any one of Embodiments K80 to K89,wherein the closed end edge is sealed to the apex of the triangular endcap using one or more of: a sewn seam, a stitched seam, an adhesiveseam, a chemically welded seam, and a thermally welded seam.

Embodiment K91 is a version of any one of Embodiments K80 to K90,wherein a bottom edge seam between the closed end edge and the bottomedge of the triangular end cap is different than a side edge seambetween the closed end edge and one or both of the side edges of thetriangular end cap.

Embodiment K92 is a version of any one of Embodiments K80 to K91,wherein the filter bag comprises a cuff attached to the filter mediaalong the opening edge of the body. Embodiment K93 is a version ofembodiment K92, wherein the cuff is thicker than the filter media.Embodiment K94 is a version of any one of Embodiments K92 to K93,wherein the cuff comprises resilient compressible material.

Embodiment K95 is a version of any one of Embodiments K80 to K94,wherein a bag support connector is attached to an exterior of the bodyproximate the closed end. Embodiment K96 is a version of embodiment K95,wherein the bag support connector comprises one of a hook and a loop.Embodiment K97 is a version of any one of embodiments K95 to K96,wherein the bag support connector is attached to the body proximate theapex of the triangular end cap.

Embodiment L98 is a filter bag comprising an opening, a closed end, abody extending from the opening to the closed end along a bag axisextending between the opening to the closed end, wherein the bodycomprises filter media taking a tubular shape that defines an interiorvolume between the opening and the closed end, and wherein the filterbag comprises a bag support connector attached to an exterior of thebody proximate the closed end.

Embodiment L99 is a version of embodiment L98, wherein the bag supportconnector comprises one of a hook and a loop.

Embodiment L100 is a version of any one of Embodiments L98 to L99,wherein the filter media comprises a closed end edge at the closed endof the bag and an opening edge at the opening of the bag; and whereinthe filter bag comprises a triangular filter bag comprising a triangularend cap comprises a bottom edge and two side edges extending away fromthe bottom edge, wherein the side edges meet at an apex of thetriangular end cap that is distal from the bottom edge; and wherein thefilter media at the closed end edge of the body is sealed to the bottomedge, the apex, and the two side edges of the triangular end cap.Embodiment L101 is a version of embodiment L100, wherein the bottomedge, apex, and two side edges of the triangular end cap define anincluded angle between the side edges at the apex of 20° or less, 15° orless, 12° or less, 10° or less, or 5° or less, and, optionally, theincluded angle is 2° or more, 3° or more, 4° or more, or 5° or more.

Embodiment L102 is a version of any one of Embodiments L100 to L101,wherein the triangular end cap, when projected onto a flat surface alongthe bag axis, defines a height between the apex and the bottom edge andalso defines a width across the bottom edge between the side edges,wherein the height is 4 or more, 6 or more, 8 or more, 10 or more, 12 ormore, or 15 or more times the width, and, optionally, wherein the heightis 20 or less, 15 or less, 12 or less, 10 or less, 8 or less, or 6 orless times the width.

Embodiment L103 is a version of any one of Embodiments L100 to L101,wherein the triangular end cap, when projected onto a flat surface alongthe bag axis, defines a height between the apex and the bottom edge andalso defines a width across the bottom edge between the side edges,wherein the height is 7 to 8 times the width.

Embodiment L104 is a version of any one of Embodiments L100 to L103,wherein the triangular end cap comprises filter media.

Embodiment L105 is a version of any one of Embodiments L100 to L103,wherein the triangular end cap is impermeable to air.

Embodiment L106 is a version of any one of Embodiments L100 to L105,wherein the body comprises a longitudinal seam extending from the closedend edge to the open edge wherein a junction of the longitudinal seamwith the triangular end cap is located along one of the side edges ofthe triangular end cap between the bottom edge and the apex of thetriangular end cap.

Embodiment L107 is a version of any one of Embodiments L100 to L106,wherein the closed end edge is sealed to the side edges of thetriangular end cap using one or more of: a sewn seam, a stitched seam,an adhesive seam, a chemically welded seam, and a thermally welded seam.

Embodiment L108 is a version of any one of Embodiments L100 to L107,wherein the closed end edge is sealed to the bottom edge of thetriangular end cap using one or more of: a sewn seam, a stitched seam,an adhesive seam, a chemically welded seam, and a thermally welded seam.

Embodiment L109 is a version of any one of Embodiments L100 to L108,wherein the closed end edge is sealed to the apex of the triangular endcap using one or more of: a sewn seam, a stitched seam, an adhesiveseam, a chemically welded seam, and a thermally welded seam.

Embodiment L110 is a version of any one of Embodiments L100 to L109,wherein a bottom edge seam between the closed end edge and the bottomedge of the triangular end cap is different than a side edge seambetween the closed end edge and one or both of the side edges of thetriangular end cap.

Embodiment L111 is a version of any one of Embodiments L100 to L110,wherein the filter bag comprises a cuff attached to the filter mediaalong the opening edge of the body. Embodiment L112 is a version ofembodiment L111, wherein the cuff comprises resilient compressiblematerial.

The complete disclosure of the patents, patent documents, andpublications identified herein are incorporated by reference in theirentirety as if each were individually incorporated. To the extent thereis a conflict or discrepancy between this document and the disclosure inany such incorporated document, this document will control.

Illustrative embodiments of the filter bags, filter bag assemblies, airfilter systems and components thereof, as well as methods of using thesame, are discussed herein some possible variations have been described.These and other variations and modifications in the invention will beapparent to those skilled in the art without departing from the scope ofthe invention, and it should be understood that this invention is notlimited to the illustrative embodiments set forth herein. Accordingly,the invention is to be limited only by the claims provided below andequivalents thereof. It should also be understood that this inventionalso may be suitably practiced in the absence of any element notspecifically disclosed as necessary herein.

1. An air filter system comprising: a tubesheet separating a housinginto a dirty air chamber and a clean air chamber, wherein the tubesheetcomprises an aperture placing the dirty air chamber in fluidcommunication with the clean air chamber, and wherein the housingcomprises an access panel located across the dirty air chamber from thetubesheet; a filter bag assembly located in the dirty air chamber, thefilter bag assembly comprising: a flange assembly comprising an interiorface and a tubesheet face facing the tubesheet, the flange assemblysurrounding the aperture in the tubesheet and comprising a clean airoutlet extending through the flange assembly, the clean air outlet influid communication with the aperture in the tubesheet; a cagecomprising a first cage end attached to the flange assembly andextending over a cage length to a second cage end distal from the flangeassembly, the cage defining a cage axis extending between the first cageend and the second cage end, the cage further comprising a plurality ofstruts extending away from the interior face of the flange assemblytowards the second cage end; and a filter bag comprising filter mediadefining an interior volume of the filter bag, wherein the filter bagextends from a first end to a second end, wherein a portion of thefilter media defines a bag opening at the first end of the filter bag;wherein the bag opening is attached to flange assembly, wherein the bagopening and the flange assembly form a seal around the clean air outletsuch that air entering the interior volume of the filter bag must passthrough the filter media of the filter bag or through the clean airoutlet of the flange assembly; a filter access port in the access panelof the housing, the filter access port comprising a cover movablebetween a closed position and an open position, wherein the cover closesthe filter access port when the cover is in the closed position andwherein the filter bag assembly can be inserted into or removed from thedirty air chamber through the filter access port when the cover is inthe open position; a seal located around the aperture in the tubesheetbetween the tubesheet face of the flange assembly and the tubesheet suchthat air passing through the aperture in the tubesheet must pass throughthe clean air outlet in the flange assembly before entering or leavingthe interior volume of the filter bag; a seal actuator proximate thefilter access port in the access panel, the seal actuator configured toapply a seal force on the second cage end through the second end of thefilter bag, wherein the seal force is directed along the cage axis andis transferred to the seal through the cage and the flange assembly; anda pulse generator located in the clean air chamber and configured todeliver pulses of air into the interior volume of the filter bag throughthe aperture in the tubesheet and the clean air outlet of the flangeassembly, the pulses of air passing through the aperture and the cleanair outlet before reaching the interior volume of the filter bag.
 2. Asystem according to claim 1, wherein the seal actuator comprises thecover of the filter access port, wherein, when the filter bag assemblyis located in mounted on the filter guide in the dirty air chamber andthe cover is in the closed position, the cover applies the seal force onthe second cage end.
 3. A system according to claim 1, wherein theflange assembly comprises a base comprising the tubesheet face of theflange assembly and a clamp configured to attach to the base on theinterior face of the flange assembly, wherein the clean air outletextends through the base and the clamp, and wherein the bag opening ofthe filter bag is retained between the clamp and the base on theinterior face of the flange assembly.
 4. A system according to claim 3,wherein the bag opening, the clamp, and the base form the seal aroundthe clean air outlet such that air entering the interior volume of thefilter bag must pass through the filter media of the filter bag orthrough the clean air outlet of the flange assembly.
 5. A systemaccording to claim 1, wherein the system comprises a filter guide in thedirty air chamber, the filter guide extending along a guide axis passingthrough the tubesheet and the access panel, wherein the guide axis isaligned with the bag axis, and wherein the filter bag assembly ismounted on the filter guide.
 6. A system according to claim 5, whereinthe flange assembly comprises a guide aperture, and wherein the filterguide passes through the guide aperture.
 7. A system according to claim1, wherein the system comprises a bag support configured to support thesecond end of the filter bag.
 8. A system according to claim 7, whereinthe bag support comprises a bag support connector attached to the filterbag proximate the second end of the filter bag, and a chamber connectorpositioned in the dirty air chamber proximate the access panel of thehousing, wherein the bag support connector and the chamber connector areconfigured to interlock with each other to support the second end of thefilter bag in the dirty air chamber.
 9. A system according to claim 8,wherein the chamber connector is attached to the filter guide.
 10. Asystem according to claim 1, wherein, in each cross-section taken in aplane transverse to the cage axis over a majority of the cage length,the plurality of struts define a triangle comprising a top vertex and apair of bottom vertices opposite the top vertex, and wherein, when thecage is located in the filter bag, the filter media of the filter bagdefines a pair of side surfaces and a bottom surface, wherein each sidesurface of the pair of side surfaces comprises a top edge proximate thetop vertex of each triangle defined by the plurality of struts, andwherein each side surface of the pair of side surfaces comprises abottom edge distal from the top edge, wherein the bottom edges of theside surfaces are proximate the bottom vertices of each triangle definedby the plurality of struts, and wherein the bottom surface of the filtermedia extends between the bottom edges of the side surfaces.
 11. Asystem according to claim 10, wherein the bottom surface of the filtermedia comprises a width measured between the bottom edges of the sidesurfaces of the filter media in a direction transverse to the cage axis,and wherein each side surface comprises a height measured between thetop edge and the bottom edge transverse to the cage axis, wherein thewidth of the bottom surface is 15% or less of the height of either sidesurface of the pair of side surfaces.
 12. A system according to claim10, wherein the clean air outlet comprises an elongated shape extendingfrom a top end to a bottom end, wherein an outlet axis extends betweenthe top end and the bottom end of the clean air outlet, and wherein aprojection of the outlet axis along the cage axis passes between thepair of bottom vertices of each triangle defined by the plurality ofstruts.
 13. A system according to claim 10, wherein the plurality ofstruts comprises a top strut and a pair of bottom struts, wherein thetop strut defines the top vertex of each triangle defined by theplurality of struts, and wherein the bottom struts define the bottomvertices of each triangle defined by the plurality of struts.
 14. Asystem according to claim 10, wherein the top vertex of each triangledefined by the plurality of struts is located between the filter guideand the bottom vertices of each triangle defined by the plurality ofstruts.
 15. A system according to claim 1, wherein the pulse generatorcomprises a plurality of ports facing the aperture in the tubesheet,wherein air in the pulses of air passes through the plurality of ports.16. A system according to claim 1, wherein the cage axis is orientedgenerally horizontally within the dirty air chamber, and wherein thehousing comprises a hopper located below the filter bag assembly,wherein particulate matter dislodged from the filter media is urgedtowards the hopper under the force of gravity.
 17. A system according toclaim 1, wherein the filter guide is located outside of the interiorvolume of the filter bag.
 18. A system according to claim 1, wherein thefilter guide is located within the interior volume of the filter bag.19. An air filter system comprising: a tubesheet separating a housinginto a dirty air chamber and a clean air chamber, wherein the tubesheetcomprises an aperture placing the dirty air chamber in fluidcommunication with the clean air chamber, and wherein the housingcomprises an access panel located across the dirty air chamber from thetubesheet; a filter guide in the dirty air chamber, the filter guideextending along a guide axis passing through the tubesheet and theaccess panel; a filter bag assembly mounted on the filter guide andlocated in the dirty air chamber, the filter bag assembly comprising: aflange assembly comprising an interior face and a tubesheet face facingthe tubesheet, the flange assembly surrounding the aperture in thetubesheet and comprising a clean air outlet extending through the flangeassembly, the clean air outlet in fluid communication with the aperturein the tubesheet, wherein the clean air outlet comprises an elongatedshape extending from a top end to a bottom end, wherein an outlet axisextends between the top end and the bottom end of the clean air outlet;a cage comprising a first cage end attached to the flange assembly andextending over a cage length to a second cage end distal from the flangeassembly, the cage defining a cage axis extending between the first cageend and the second cage end, the cage further comprising a plurality ofstruts extending away from the interior face of the flange assemblytowards the second cage end, wherein, in each cross-section taken in aplane transverse to the cage axis over a majority of the cage length,the plurality of struts define a triangle comprising a top vertex and apair of bottom vertices opposite the top vertex; and a filter bagcomprising filter media defining an interior volume of the filter bag,wherein the filter bag extends from a first end to a second end, whereina portion of the filter media defines a bag opening at the first end ofthe filter bag; wherein the bag opening is attached to flange assembly,wherein the bag opening and the flange assembly form a seal around theclean air outlet such that air entering the interior volume of thefilter bag must pass through the filter media of the filter bag orthrough the clean air outlet of the flange assembly; wherein, when thecage is located in the filter bag, the filter media of the filter bagdefines a pair of side surfaces and a bottom surface, wherein each sidesurface of the pair of side surfaces comprises a top edge proximate thetop vertex of each triangle defined by the plurality of struts, andwherein each side surface of the pair of side surfaces comprises abottom edge distal from the top edge, wherein the bottom edges of theside surfaces are proximate the bottom vertices of each triangle definedby the plurality of struts, and wherein the bottom surface of the filtermedia extends between the bottom edges of the side surfaces; a filteraccess port in the access panel of the housing, the filter access portcomprising a cover movable between a closed position and an openposition, wherein the cover closes the filter access port when the coveris in the closed position and wherein the filter bag assembly can beinserted into or removed from the dirty air chamber when the cover is inthe open position, wherein the cover acts on and forces the tubesheetface of the flange assembly against the tubesheet when the filter bagassembly is mounted on the filter guide and the cover is in the closedposition; and a pulse generator located in the clean air chamber andconfigured to deliver pulses of air into the interior volume of thefilter bag through the aperture in the tubesheet and the clean airoutlet of the flange assembly, the pulses of air passing through theaperture and the clean air outlet before reaching the interior volume ofthe filter bag.
 20. A method of sealing a filter bag over an aperture ina tubesheet of an air filter system, the method comprising: positioninga filter bag assembly in a dirty air chamber of an air filter systemwith a flange assembly of the filter bag assembly located proximate thetubesheet, wherein a bag opening of a filter bag of the filter bagassembly is located over the aperture in the tubesheet, and wherein theflange assembly covers the aperture; and forcing the flange assemblyagainst the tubesheet by applying a compression force on a cage locatedin an interior volume of the filter bag, wherein the cage is attached tothe flange assembly and extends away from the flange assembly towards aclosed end of the filter bag; wherein air passing through the aperturein the tubesheet from the dirty air chamber must pass through the filterbag before reaching the aperture.
 21. A method according to claim 20,wherein the compression force is applied on the cage through the filterbag.
 22. A method according to claim 20, wherein the compression forceis applied by closing an access port into the dirty air chamber, whereinthe access port is located across the dirty air chamber from thetubesheet.
 23. A method according to claim 20, wherein the positioningthe filter bag assembly in the dirty air chamber comprises passing thefilter bag assembly into the dirty air chamber through the access port.24. A method according to claim 20, wherein the positioning the filterbag assembly in the dirty air chamber comprises passing the filter bagassembly into the dirty air chamber through the access port, and whereinthe filter bag is attached to the flange assembly before the filter bagassembly is passed into the dirty air chamber through the access port.25. A triangular filter bag comprising an opening, a closed end, a bodyextending from the opening to the closed end along a bag axis extendingbetween the opening to the closed end, and a substantially triangularend cap attached to the body at the closed end; wherein the bodycomprises filter media taking a tubular shape that defines an interiorvolume between the opening and the closed end, wherein the filter mediacomprises a closed end edge at the closed end of the bag and an openingedge at the opening of the bag; wherein the triangular end cap comprisesa bottom edge and two side edges extending away from the bottom edge,wherein the side edges meet at an apex of the triangular end cap that isdistal from the bottom edge; and wherein the filter media at the closedend edge of the body is sealed to the bottom edge, the apex, and the twoside edges of the triangular end cap.
 26. A triangular filter bagaccording to claim 25, wherein the bottom edge, apex, and two side edgesof the triangular end cap define an included angle between the sideedges at the apex of 20° or less and 2° or more.
 27. A triangular filterbag according to claim 25, wherein the triangular end cap, whenprojected onto a flat surface along the bag axis, defines a heightbetween the apex and the bottom edge and also defines a width across thebottom edge between the side edges, wherein the height is 4 or moretimes the width and wherein the height is 20 or less times the width.28. A triangular filter bag according to claim 27, wherein a bag supportconnector is attached to an exterior of the body proximate the closedend.
 29. A triangular filter bag according to claim 28, wherein the bagsupport connector comprises one of a hook and a loop.
 30. A triangularfilter bag according to claim 28, wherein the bag support connector isattached to the body proximate the apex of the triangular end cap.